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Molecular orbital theory and e-EDM in molecules Minori Abe 阿部穣里 Tokyo Metropolitan University 首都大学東京 CP VIOLATION IN ELEMENTARY PARTICLES AND COMPOSITE SYSTEMS Advanced School

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Page 1: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Molecular orbital theoryand

e-EDM in molecules

Minori Abe阿部穣里

Tokyo Metropolitan University首都大学東京

CP VIOLATION IN ELEMENTARY PARTICLES AND COMPOSITE SYSTEMS Advanced School

Page 2: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Contents• Fundamental view of molecular orbital theoryI. Hydrogen atomII. H2

+ moleculeIII. H2 moleculeIV. Diatomic moleculesV. ExercisesVI. Hartree-Fock (HF) theoryVII. Basis set functionsVIII. Beyond the HF theoryIX. Relativistic theory• Electron-EDM in moleculesI. Physical pictureII. MethodologyIII. Some results

Page 3: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Reference books

• Physical Chemistry A Molecular Approach by D. A. McQuarrie & J. D. Simon

• Modern Quantum Chemistry Introductions to Advanced Electronic Structure Theory by A. Szabo, N. S. Ostland

• Molecular Electronic Structure Theory by T. Helgaker, P. Jorgensen, J. Olsen

Page 4: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

In quantum mechanics,

Kinetic energy operator + Potential energy operator

= Hamiltonian operator

Energy is obtained as an Energy is obtained as an eigeneigen value of the value of the Hamiltonian operator. Hamiltonian operator. Eigen function is called as wave function.Eigen function is called as wave function.

Quantum Mechanics: time-independent Schrödinger equation

In classical mechanics(Kinetic energy:T)+(Potential energy:V)=Total Energy

EVTH ˆˆˆ

T V

zyx ,,:

EH

Page 5: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

Erε

ezyxm

H

0

2

2

2

2

2

2

22

42ˆ

222 zyxr

Invert “Cartesian coordinate x, y, z”to “polar coordinate r, q, q”

cossinsincossin

rzryrx

electron charge -e

Nucleus(proton)charge +e

Hydrogen atom

Like the latitude and longitude of earth!

2

Page 6: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

Erε

ezyxm

H

0

2

2

2

2

2

2

22

42ˆ

222 zyxr

We can solve R(r), qqqq, q qq) independently.

,ΦΘ,, YrRrRr

0422 0

2

2

22

2

2

rRE

re

rmdrdRr

drd

rm ee

,sinsinsin 22

2

YYY

Page 7: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

042

12 0

2

2

22

2

2

rRE

re

rmll

drdRr

drd

rm ee

,sinsinsin 22

2

YYY

imm

lml eP

mlmllY cos

!!

412,

2/1

0

1223

0

21

3

22!2!1

0

narLer

nalnnlnrR l

lnnarl

l

nl

Associated Associated LaguerreLaguerre polynomialspolynomials

Associated Legendre polynomialsAssociated Legendre polynomials 1 ll

Spherical harmonics

Radial function

Page 8: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atomThree integers come up when solving Schrödinger equation of H atom.

,,,,,mlnlmln YrRr

Radial functions depend on n and l.Spherical harmonics depend on l and m.

200

4

2220

2

4

832 naem

nemE ee

n

Energy only depends on n quantum numbers.

2

20

04

ema

e

Bohr radius

n:prinsiple quantum number (n = 0, 1, 2, …)l: angular momentum quantum number (l = 0, …, n)m: magnetic quantum number (m= -l, -l+1, ..., l-1, l)

Page 9: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

Examples

0

23

00,0,1 exp1,,

aZr

aZr

00

23

00,0,2 2

exp2321,,

aZr

aZr

aZr

cos2

exp321,,

00

23

00,1,2

aZr

aZr

aZr

iaZr

aZr

aZr

expsin

2exp

641,,

00

23

01,1,2

… 1s orbital

… 2s orbital

… 2p0 orbital

… 2p1, 2p-1 orbital

p1, p-1 orbitals are complex functions.

Page 10: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atomp1 and p-1 are energetically degenerated. Besides, they have same probability density function.

2211

211 sin

83,, YY

Take linear combinations of p1 and p-1 as bellow.

sinsin43

21 21

11

11

YY

ip y

cossin

43

21 21

11

11

YY

ipx

px, py orbitals are now real functions with same eigenenergy (but no more than the eigen function of m).

px py pz

Page 11: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

1cos3165 2

21022

Yd

z

Similarly, we take linear combinations of d orbitals to make real functions as follows,

coscossin415

21 21

12

12

YYd xz

sincossin415

21 21

12

12

YY

id yz

2cossin1615

21 2

212

22222

YYd

yx

2sinsin1615

21 2

212

222

YY

id xy

These d functions are real and possible to show as pictures.Molecular calculations use the real functions as basis sets.

Page 12: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

Radial function of 1s orbital

0

23

00,0 exp4

aZr

aZrR

Page 13: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

Radial distributed functions of 1s orbital

0

23

00,0 exp4

aZr

aZrR

Page 14: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

Radial distributed functions of 2s orbital

00

23

00,2 exp2

241

aZr

aZr

aZrR

There is a node where electron density is zero.

Page 15: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Schrödinger equation of Hydrogen atom

Radial distributed functions of 2p orbital

00

23

01,2 exp

121

aZr

aZr

aZrR

Page 16: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

He atom

Still it requires some approximations such as perturbation theory or variational theory.

21

21210

2

20

2

10

2

2122

221

22

2

,,

,,44

24

2

,,222

rr

rrrrrr

rr

R

RRR

R

E

eee

mmM ee

electron charge -e

He nucleuscharge +2e

r1

r2

R

Hamiltonian

2121210

2

20

222

21

2

,,4

1142

2rrrr

rr

Ee

rre

m 1e

If we ignore nucleus motion and take origin on the nucleus,

Page 17: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

electroncharge -e

Nucleus(proton)charge +e

rA

R

rB

HBHA

R,rER,rR

er

er

e

R,rmMM

BA

eBA

0

2

0

2

0

2

22

22

22

444

222

If we ignore nucleus motion and consider only electronic state by fixing nuclear places…

R,rRER,rR

er

er

em eee

BAe

0

2

0

2

0

22

2

4442

Hamiltonian

Born-Oppenheimer approximation

RR,rR,r ne

Page 18: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

Introduce atomic unit

R,rRER,rR

er

er

em eee

BAe

0

2

0

2

0

22

2

4442

Simplified!

R,rRER,rRrr eee

BA

111

21 2

mass emua ..1

charge eua ..1

length 2

20

04..1

emaua

e

Energy00

2

4..1

aeEua hartree

Page 19: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

Let’s consider the wave function is represented as a linear combination of 1s orbitals of nucleus HA and HB.

R,rRER,rRrr ee

BA

111

21 2

RHBHA

1sA 1sB

R,rcR,rcR,rBA sBsAe 11

Linear Combination of Atomic Orbital (LCAO)

0

23

01 exp1

aZ

aZR,r

AsARr

0

23

01 exp1

aZ

aZR,r B

sB

Rr

Page 20: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

E is expressed as follows.E is expressed as follows.

Hd

HdE

ˆˆ

r

r

R,rRER,rRrr ee

BA

111

21 2

EH ˆ

ABBA ssssBAAB HHHH 1111ˆˆ

BBAA ssssBBAA HHHH 1111ˆˆ

SSSABBA ssssBAAB 1111

11111 BBAA ssssBBAA SS

SccccHccHcHcE

BABA

ABBABBBAAA

22

22

22

Page 21: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

JERrrRrr

H

S

sB

ssA

ssBA

sAA AAAAAA

1

1112

112

1111

21111

21

Atomic orbital (AO) integral of H2+

KSEKE

RrrRrrH

SssS

sA

ssB

ssBA

sAB

BA

AABABA

1111

1112

112

1111

21111

21

RR

RrssdRr

J

B

AA

sB

s AA

112exp111

1111

r

RRRS

RS

rssdRr

K

A

BA

sA

s BA

1exp11

1111

r

3

1exp2

11RRRS

BA ss Overlap integral

Coulomb integral Exchange integral

We can fortunately calculate these integrals analytically as functions of R.

Page 22: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

Differentiate the above equation with cA or cB

and insert or .

Differentiate the above equation with cA or cB

and insert or .

ABBABBBAAABABA HccHcHcSccccE 22 2222

0

AcE

0

2222

2222222

BABAAA

ABBAAABA

ABBAAABABABAA

cESHcEHHcHcSccE

HcHcSccEScccccE

0

BcE

0

2222

2222222

BBBAAB

ABABBBAB

ABABBBABBABAB

cEHcESHHcHcSccE

HcHcSccEScccccE

Variational theory

Page 23: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

To have non trivial solution of cA and cB

must be hold.

To have non trivial solution of cA and cB

must be hold.

0 BABAAA cESHcEH

0 BBBAAB cEHcESH

0

ESHEHEHESH

ABBB

BBABSecular equation

022 EHESH AAAB

SHHE

SHHE ABAAABAA

1,

1 EHESH AAAB

Page 24: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

SHHE ABAA

1WhenWhen

011

BABAA

ABAABAA

AA cSSHHHc

SHHH

BA

BAAABAABAA

BABAAABAABAAAA

cccSHHcHSH

cSHHSHcHHSH

0

011

SHHE ABAA

1WhenWhen

011

BABAA

ABAABAA

AA cSSHHHc

SHHH

BA

BAAABAABAA

BABAAABAABAAAA

cccSHHcHSH

cSHHSHcHHSH

0

011

Page 25: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

SHHE ABAA

1

From the normalization condition of , From the normalization condition of ,

WhenWhen BA cc

BBAA cc

12

222

22

Scccc

cccc

BABA

BABABBBAAA

Scc

Sccc

BA

AAA

221

12 222

Scc

Sccc

BA

AAA

22112 222

BA cc

should be satisfied.should be satisfied.

WhenWhen

BAS

22

1 BAS

22

1

SHHE ABAA

1

Page 26: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

RHBHA

H2+ molecule

RHBHA

RHBHA

RHBHA

BA

BA

Page 27: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

+ + -

Electron density

Molecular orbital

q+

q2+ q2

-

q -

Binding orbital

anti-binding orbital

SHHE ABAA

1SHHE ABAA

1Node

Large electron Large electron density between density between

the nucleithe nuclei

Page 28: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2+ molecule

+

+ -

Molecular orbital

q+

q -

binding orbital

anti-binding orbital

SHHE ABAA

1

SHHE ABAA

1

10,0,0 SHH ABAA

qE-=E- - E1S

qE+=E+ - E1S

There is a minimum in the energy curve of E+. (Binding)

H + H+

q -

Page 29: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2 moleculeelectronscharge -e

Nucleus(proton) charge +e

r1A

R

r2B

HBHA

r2Ar2A

r12

+

+ -

q+

binding orbital

anti-binding orbital

SHHE ABAA

1

SHHE ABAA

1

Let’s assume two electrons occupy in binding orbital of H2+.

qq spinspin qq spinspin

q -

212121

!21

22221111

!212,1

To consider anti-symmetry of electronic wave function,we introduce Slater determinant.

1,22,1

Page 30: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2 moleculeelectronscharge -e

Nucleus(proton) charge +e

r1A

R

r2B

HBHA

r2Ar2A

r12

2121

212112

212211

22

21

11

111121

21

,rR,rRE,rR,rH

,rR,rR

,rR,rr

,rR,rrrrr

ee

ee

eBABA

Hamiltonian

2121

2

212121

2121

2121!2

1

rHrdd

ddrHrdd

,rR,rH,rR,rRE ee

rr

rr

1

Page 31: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

H2 molecule

Experiment

Re (calculated) = 0.85 Å

Re (experiment) = 0.741 Å

De (calculated) = 260 kJ/mol

De (experiment) = 457 kJ/mol

These values are improved when we consider molecular orbital optimized for H2 by the Hartree-Fock method.

Re (HF limit) = 0.741 Å

De (HF limit) = 351 kJ/mol

Page 32: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Diatomic molecular orbitals and p orbital interaction

Binding

Anti-binding

Binding

Binding

Anti-binding

Anti-binding

q

qq

q2pzq

q2pz

qsq

qs

+ - + - + - +-

doubly degenerated

Page 33: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Homo-nucleus diatomic molecular orbital

qqu qqq2pzqq

qqu qqqq

qqg qqq2pz qqqg

qqu qq2sqq

qqg qq2s q

qqu qq1sqq

qqg qq1s q

Page 34: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Diatomic molecular orbitalMolecular orbitals

ml=0

ml=-1,1

In homoIn homo--nuclear nuclear molecules, bonding molecules, bonding orbitals are notated orbitals are notated with subscript g with subscript g ((geradegerade) and anti) and anti--bonding orbitals are bonding orbitals are with u (with u (ungeradeungerade).).

ml=-1,1

ml=0

ml=0

ml=0

ml=0

ml=0

|ML | =0, q|ML | =1, q|ML | =2, q

……

ML :sum of ml

Terms

g×g=gu×g=uu×u=g

2S+1q (g or u)

q

qqis determined from Ml.

qqu qqq2pzqq

qqu qqqq

qqg qqq2pz q

qqg

qqu qq2sqq

qqg qq2s q

qqu qq1sqq

qqg qq1s q 2q g

Page 35: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Diatomic molecular orbitalMolecular orbitals

ml=0

ml=-1,1

In homoIn homo--nuclear nuclear molecules, bonding molecules, bonding orbitals are notated orbitals are notated with subscript g with subscript g ((geradegerade) and anti) and anti--bonding orbitals are bonding orbitals are with u (with u (ungeradeungerade).).

ml=-1,1

ml=0

ml=0

ml=0

ml=0

ml=0

ML=0, qML=1, qML=2, q

……

ML :sum of ml

Terms

g×g=gu×g=uu×u=g

q

qqis determined from Ml.

qqu qqq2pzqq

qqu qqqq

qqg qqq2pz q

qqg

qqu qq2sqq

qqg qq2s q

qqu qq1sqq

qqg qq1s q 3qg

2S+1q (g or u)

Page 36: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Diatomic molecular orbitalMolecular orbitals

ml=0

ml=-1,1

In homoIn homo--nuclear nuclear molecules, bonding molecules, bonding orbitals are notated orbitals are notated with subscript g with subscript g ((geradegerade) and anti) and anti--bonding orbitals are bonding orbitals are with u (with u (ungeradeungerade).).

ml=-1,1

ml=0

ml=0

ml=0

ml=0

ml=0

ML=0, qML=1, qML=2, q

……

ML :sum of ml

Terms

g×g=gu×g=uu×u=g

q

qqis determined from Ml.

qqu qqq2pzqq

qqu qqqq

qqg qqq2pz q

qqg

qqu qq2sqq

qqg qq2s q

qqu qq1sqq

qqg qq1s q 2q u

2S+1q (g or u)

Page 37: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Diatomic molecular orbital

Configurations and terms

Page 38: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Homo-diatomic molecular orbital

Oxigen is paramagnetic!

Electrons occupy the orbitals under the Fund’s rule.

Page 39: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Homo-diatomic molecular orbitalWhen bonds are strong?

(Bond order) = [(number of elec. in bonding orbital)- (number of elec. in anti-bonding orbital)]/2

q2pzq

qq

q2pz

q

Example of N2

(bond order)=(6-0)/2=3

N N

Page 40: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Homo-diatomic molecular orbital

Bond order

Bond energy(kJ/mol)

Bond length (pm)

Page 41: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Homo-diatomic molecular orbitalElectron density of molecular orbitals

Page 42: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Hetero-diatomic molecular orbital

2pzF 1sH 2pxF

(or 2pyF)1sH

They can interact!They createq and qqorbitals.

They cannot interact!

x

1sH

2pxF

(or 2pyF) 2px,y,zF

qq

q

Example of HF molecule

0ˆ,0ˆ

0ˆ,0ˆ0ˆˆ0ˆˆ

0

0

yBmolAxBmolA

yAmolAxAmolA

BmolAzBmolA

AmolAzAmolA

pHspHs

pHspHs

pHspHs

pHspHs

0ˆ,0ˆ,0ˆ

0

1

1

pHs

pHs

pHs

atom

atom

atom

Only pz orbital can interact with s orbital of other atom.px and py remain as lone pairs.

Page 43: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Hetero-diatomic molecular orbitalExample of HF molecule

2px F

q(1s H + 2s F)

qqq(1s H + 2pz F)

1s F

q(1s H + 2pz F)

2py F

doubly degenerated

Page 44: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Vibration and Rotation

Total Molecular energy = E(R) + Evib + Erot

Electronic energy Nuclear Schrödinger equation

Rigid Rotator model

After obtaining electronic energy (E(R)), we can calculate vibrational and rotational levels.

R

Page 45: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

General Hamiltonian for molecule

ee

N

jiji

N

BABA ABij

N

i

N

A iAi

ee

ERrr

EHe ne n

)(, )(,1 1

2 11121

n

ee

ee n

N

BA AB

N

iij

N

ji ij

N

ii

N

i

N

A iAi

RVR

gr

hr

1

ˆ1

ˆ121

1

11 1

2One-electron operator

Two-electron operator

Nuclear potential (Constant)

Page 46: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Slater determinant for moleculeSlater determinant

Energy (i.e. Expectation value of single Slater determinant)

eeee

e

e

NNNN

N

N

N

...............

...

...

det!

1

21

22221

11211

RVjiijijijhRV

rr

hHE

ee

e

e

N

ji

N

iii

N

jiijjijiji

N

iii

1

2112

212112

21

1

11

ˆ

AON

ppipi c

1

One-electron spin-orbital

Page 47: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Fock operator

……(After some algebra)……

11

1212

221212

2211

111

ˆˆ

11ˆ

ˆˆ

ii

N

ijjijijjiHF

HF

KJ

rd

rdv

vhfe

One electron wave functions should be the eigen functions of the Fock operator. iiif ˆ

E should be minimized for all under the orthonomal conditions of .Let’s consider a Lagrangian as follows.

Impose the first order variation of Lagrangian to be zero.

n

jiijjijiEL

,

iijji

Page 48: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

AON

ppipi c

1

Hartree-Fock-Roothaan equation

AOAO N

ppipi

N

ppip ccf

11

ˆ

iiif ˆ

q

AOAO N

ppqipi

N

ppqip cfc

11

ˆ

AOAO N

ppiqpi

N

ppiqp cScF

11

Multiply

and integrate

Expand by AO (basis set)C is molecular orbital coefficient

SCεFC

Hartree-Fock Roothaan equation

Page 49: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Hartree-Fock-Roothaan equationF matrix actually depends on molecular orbital information due to the two-electron operators.

SCεCCF

We need to solve it iteratively.

Non linear equation!

εSCCCF 11 nnn

thresholdnn CC 1 Converged!

N

srrspqpq rqpsrspqDhF

,

2 elecN

iqipipq CCD

Density matrix

Page 50: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Hartree-Fock-Roothaan equation

1121

2112

2121

11

2121

1

2

ˆ

1

1211

21ˆ

qpqppq

sqrp

q

N

A Apq

N

A Appq

ddS

rddrspq

rdd

rh

nn

N

srrspqpq rqpsrspqDhF

,

2

To solve Hartree-Fock-Roothaan equation, we need to calculate these integrals with the atomic basis set orbital.We need efficient functions for basis sets.

kinetic

Nuclear attraction

Two-electron repulsion

Overlap

Page 51: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Basis set functionsIn poly-atomic systems, polar coordinate is no more useful because we have various centers in a molecule.

222exp

exp

AAA ZzYyXx

r

222

22

22

2

expexpexp

exp

exp

exp

AAA

AAA

AAA

ZzYyXx

ZzYyXx

ZzYyXx

r

Slater orbital (1s)

Gaussian orbital (1s)

Nucleus A(XA, YA, ZA)

1s orbital Nucleus B(XB, YB, ZB)

Nucleus C(XC, YC, ZC)

We can separate x, y, z variable easily.

Page 52: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Basis set functions

Nucleus A(XA, YA, ZA)

1s orbital Nucleus B(XB, YB, ZB)

Gaussian product rulesTwo-Gaussian product

one Gaussian at another center

Page 53: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Basis set functions

2

2

2

22

22

exp

exp

exp

exp

expexp

PPPPz

PPPy

PPPx

BBAA

BBAA

ZzzAdA

YyydA

XxdxA

rrdydzdx

rrdydzdx

Ex. Overlap of two centers

Nucleus A(XA, YA, ZA)

1s orbital Nucleus B(XB, YB, ZB)

Easy to calculate!

Page 54: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Basis set functions

xzYYrd xz 312

12

2

yzYYri

d yz 321 1

212

2

2222

22

2 321

21

22 yxYYrdyx

xyYYri

d xy 321 2

222

2

2202

2 321

2 rzYrdz

If we consider Cartesian functions, it’s written by very simple polynomials of x, y, and z for higher angular parts.

Ex. Form of d orbital basis except exponential partEx. Form of d orbital basis except exponential part

Page 55: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Basis set functions

q=1.24

q=1.24

Gaussian function is flat at r=0whereas Slater function has a cusp.Gaussian function is flat at r=0whereas Slater function has a cusp.

Comparison between Gaussian and Slater functions

Page 56: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Basis set functionsSlater functions are fitted by the linear combination of three Gaussian functions.STO-3G

contraction basis setcontraction basis set

STO-3G is close to the Slater function when r is larger than a0.

Exponential coefficientsd contraction coefficients

Page 57: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Basis set functionsIn the sense of linear combination of atomic orbital (LCAO), we usually use contracted-Gaussian basis functions.Contraction coefficients are normally determined from atomic calculations.

To describe molecular bonds well;

1. we decontract or split basis sets for valence orbitals. (Ex“valence double-zeta”)

2. We sometimes add diffuse functions, with small exponent coefficients.

3. We sometimes add polarization functions, higher angular momentum functions.

Page 58: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Basis set functionsDyall-QZ-c basis S 1s 2s 3s 4s 5s 6s6.5973426E+07 9.9782180E-05 -3.7200758E-05 1.7519609E-05 8.5062625E-06 3.2603668E-06 -8.3449817E-071.7573042E+07 2.3885301E-04 -8.9322205E-05 4.2086226E-05 2.0436349E-05 7.8332122E-06 -2.0049375E-066.0368629E+06 4.8228463E-04 -1.8095458E-04 8.5305558E-05 4.1427940E-05 1.5879797E-05 -4.0644893E-062.3148616E+06 8.8873685E-04 -3.3516266E-04 1.5812708E-04 7.6807417E-05 2.9441998E-05 -7.5358548E-069.7498001E+05 1.6115692E-03 -6.1126323E-04 2.8865029E-04 1.4023603E-04 5.3759158E-05 -1.3759946E-054.3572342E+05 2.8710341E-03 -1.0971913E-03 5.1870929E-04 2.5207492E-04 9.6635219E-05 -2.4734770E-052.0470199E+05 5.1348039E-03 -1.9786885E-03 9.3667476E-04 4.5532856E-04 1.7457384E-04 -4.4683531E-059.9654250E+04 9.2072616E-03 -3.5840701E-03 1.6992363E-03 8.2632136E-04 3.1681877E-04 -8.1094980E-054.9983316E+04 1.6583606E-02 -6.5322387E-03 3.1029055E-03 1.5095694E-03 5.7888801E-04 -1.4817268E-042.5663485E+04 2.9818647E-02 -1.1931486E-02 5.6815266E-03 2.7657042E-03 1.0606081E-03 -2.7149014E-041.3440699E+04 5.2950673E-02 -2.1662469E-02 1.0353665E-02 5.0443789E-03 1.9350958E-03 -4.9532159E-047.1598929E+03 9.0977035E-02 -3.8543746E-02 1.8528281E-02 9.0395936E-03 3.4681500E-03 -8.8782782E-043.8753556E+03 1.4628804E-01 -6.5598978E-02 3.1847069E-02 1.5573611E-02 5.9794889E-03 -1.5306719E-032.1307057E+03 2.0889813E-01 -1.0286939E-01 5.0763430E-02 2.4921791E-02 9.5740825E-03 -2.4513911E-031.1898903E+03 2.4396201E-01 -1.3823205E-01 7.0048345E-02 3.4607750E-02 1.3320170E-02 -3.4104986E-036.7429769E+02 2.0474701E-01 -1.3342031E-01 6.9688307E-02 3.4691717E-02 1.3362843E-02 -3.4233136E-033.8724214E+02 1.0102651E-01 -2.4179884E-02 8.1792671E-03 3.5358781E-03 1.3346475E-03 -3.3860593E-042.2481397E+02 2.1298438E-02 2.1261417E-01 -1.5951971E-01 -8.6463521E-02 -3.4004530E-02 8.7246883E-031.3362161E+02 1.3981505E-03 4.1121363E-01 -3.7713017E-01 -2.1585010E-01 -8.5749185E-02 2.2051823E-028.1281158E+01 4.1116786E-05 3.5057833E-01 -4.0182068E-01 -2.4250758E-01 -9.7776272E-02 2.5149688E-025.0939803E+01 3.8127887E-05 1.4856492E-01 -1.0447585E-01 -6.8770856E-02 -2.8918209E-02 7.5361505E-033.2280526E+01 -1.0441931E-04 2.9528209E-02 4.0069785E-01 3.6353582E-01 1.6166297E-01 -4.2214557E-022.0394685E+01 3.6942048E-05 1.8089816E-03 6.1447118E-01 7.4823240E-01 3.5515598E-01 -9.3081510E-021.2503244E+01 -3.2526750E-05 3.5775229E-04 3.2470347E-01 3.7866373E-01 1.6908482E-01 -4.4203642E-027.2874456E+00 2.4471759E-05 -3.1026960E-04 5.4055539E-02 -4.6352619E-01 -2.8413146E-01 7.6523038E-024.3210001E+00 -1.1535675E-05 3.3408769E-05 2.2180494E-03 -7.3973061E-01 -5.9688417E-01 1.6916103E-012.5234051E+00 8.3346020E-06 -7.0668008E-05 1.2025946E-03 -3.2042059E-01 -3.8288855E-01 1.1465921E-011.4175240E+00 -4.8775188E-06 3.8350509E-05 -2.7428342E-04 -3.8335074E-02 2.2717730E-01 -7.9496271E-027.9157400E-01 2.7643534E-06 -1.7666327E-05 9.1058439E-05 -1.4535011E-03 6.2283403E-01 -2.2484198E-014.4198499E-01 -1.7465836E-06 1.3620169E-05 -9.8219827E-05 -7.9721646E-04 4.5570588E-01 -2.7116462E-012.4345371E-01 8.5919476E-07 -6.0619634E-06 3.2241392E-05 -6.7667385E-05 1.0609629E-01 -1.5553717E-011.1878413E-01 -4.2231693E-07 3.0886469E-06 -1.6573828E-05 3.8028070E-05 5.1623573E-03 1.8463795E-016.1739139E-02 2.3280153E-07 -1.6835017E-06 1.4079000E-05 2.1992554E-04 3.9420751E-03 5.2053680E-013.1922684E-02 -9.6968198E-08 7.1602848E-07 -3.7927686E-07 1.6873698E-04 3.2883261E-03 4.4423560E-011.6420495E-02 2.3449273E-08 -1.6889708E-07 1.6939352E-06 3.5436438E-05 6.4944623E-04 8.6473321E-02

exponential coefficients

contraction contraction coefficientscoefficients

quadruplequadruplezetazeta

Page 59: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

212121!2

122221111

!212,1

212121!2

122221111

!212,1

There is no reason that the Single determinant can really describe the true wave function.

These are different functions!

Mixing the various determinants (configurations) improve the solution. (Configuration interaction)

Beyond the HF method

Page 60: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Beyond the HF methodIf we consider the wave function as the linear combination of full configurations (Full-CI) with infinite number of orthogonal 1-electron orbital basis, it should be “Exact”.(Of course, impossible. Number of basis sets is finite!)We need approximation methods.

Major approximation methods(post-HF or electron correlation method)

Perturbation theory; MP2, MP4, … (Truncated) configuration interaction theory; SDCI,SDTQCI,…,RASCICoupled Cluster theory; CCSD, CCSDT, …

More accurate

Multi reference electron correlation methods will be discussed in Dr. Geetha’s talk.

Page 61: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Single and Doubles CI method

: N-electron excitation operator

HFCIFull TTTt 3210ˆˆˆ

NT

occivira

iaoccivira

HFaaiatia

iatT,

1,

11 ,,ˆ

t1, t2, … coefficients are the parameters to be obtained.

Creation and Annihilation operator(delete i and create a orbital)

HFSDCI TTt 210ˆˆ

SDCISDCISDCI HE ˆ

t0, t1, t2 coefficients are optimized as the energy is to be minimum.(Please read Szabo’s book! for more details.)

Exact within the used basis sets!

Page 62: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

occjivirba

iajb

occjivirba

HFaaaajibatijab

T ,,,22

Ex. Two electron excitation operator

HF

ij

ba

ij

ba

ijab

iajb

ibja

or

(a > b, i > j)

HFaaaaHFaaaaHFaaaaHFaaaa jaibibjajbiaiajb

a, b,c: virtual orbitali,j,k: occupied orbitalp: general orbital

Page 63: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Coupled Cluster methodOne of the most accurate methods to take into account

electron correlation within single reference theory

HFN EHH

HFHFHFHF EH

HFHFN TETH

expexp

321 TTTT : N-electron excitation operator

HFHFexact

TTT

2

ˆˆ1ˆexp2

exactexact EH ˆ

EElectron correlation energy

NT

HFHFN ETHT

expexp

occivira

iaoccivira

HFaaiatia

iatT,

1,

11 ,,ˆ t1, t2, … coefficients are the parameters to be obtained.

Page 64: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Coupled Cluster method

CN

NNNN

N

TH

TTTTHTTHTHH

THT

exp

,,,,!41...,,

!21,

expexp

0exp HFCNai TH

0exp HFCNabij TH

ETH HFCNHF exp

21 TTT

The above exponential expansion is terminate after four commutations because HN is at most two-electron operator.

means collect only connected terms which provide non-zero values.

CN TH exp

Coupled Cluster singles and doubles (CCSD) equations

abij

ai One-electron excited determinant

Two-electron excited determinant

... (1)

... (2)

Page 65: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

CCSD amplitude equations

CLK

ACKL

KLIC

DCK

CDIK

AKCD

CK

CK

AKIC

CK

CI

AK

ACIK

KC

K

AK

KI

C

CI

AC

CK

CI

AK

KC

AI

VVTV

TTTHTHTHTTFF

,,,

,,

0

2

0,,

CK

BK

CJ

AKIC

CK

CBKJ

AKICABIJ

DC

CDIJ

ABCD

LK

ABKL

KLIJ

C

CJ

ABIC

K

BAJK

KIIJ

K

BK

ABIJ

C

CBIJ

ACAB

ABIJ

TTVTHPPBA

TVTGPTVTGPV

Term notation of DIRAC08 RELCCSD from L. Vischer’s JCP paper

... (1)

... (2)

Non linear equations of T1 and T2, iteratively to be solved.

BAJI

ABIJ

IJAB

AI

AI

IACCSD VTFEE

,,

Page 66: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Problem in coupled cluster method for expectation value

For expectation value, CC method do not terminate in expansion. (Note that not inverse but dagger in bra part.)

HFTTTTHF

HFTTOTTHF

ON

N

2

ˆˆ12

ˆˆ1

2

ˆˆ1ˆ2

ˆˆ1

22

22

We need to use more complicated methodto get expectation value.We can calculate expectation value by solvingLambda equation, but it requires another effort.(Both programming and computational time)

Page 67: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Relativistic Quantum Chemistry

Page 68: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Non-relativistic quantum mechanics

Et

izyxm

H

2

2

2

2

2

22

Time dependent Schrodinger equation for free particle

tzyx ,,,

First-differential equation with respect to time but Second-differential equation with respect to space.

The Schrodinger equation is Lorenz variant and no-relativity!

2

2

2 1,,,

1

cVxttzzyyVtxx

Page 69: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Dirac equation

Et

imcc

)( 2pα

Dirac equation is Lorenz invariant and correspond to Schrodinger equation when v/c goes to 0 (non-relativistic limit).Relativistic quantum mechanics!

0pσpσ0

pαλ

λ

1001

β

zyi

x

yi

xzipσ

1001

1

S

S

L

L

First differential of space First-differential of time

Page 70: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Dirac equation

Et

imcc

)( 2pα

Complicated features1. Four-dimensional matrix operator2. Four-dimensional component in solution3. Negative energy states continue to minus infinity…⇒indicating the existence of anti-particle of electron. (positron)

0pσpσ0

pαλ

λ

1001

β

zyi

x

yi

xzipσ

1001

1

S

S

L

L

First differential of space First-differential of time

Page 71: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Merits of Dirac equation• We can solve Dirac equation analytically for Hydrogen

atom.

• What’s the mean of four component?

Information of positronic states

Information of spin

Large component for electron; up spinLarge component for electron; down spinSmall component for electron; up spinSmall component for electron; down spin

S

S

L

L

2 × 2 = 4

1s0

01s

Example of two-component structure by introducing spin 1s 1s

Page 72: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Solution of Dirac equation of H atom

Up spin and down spin are mixed in one-electron orbital.

Relativistic effect related with spin:Spin-orbit interaction

Up spin componentDown spin component

11 ipp

0p

2121

pFor Ex.

Page 73: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Spin-orbit interactionエネルギー

s

p

d

f

p+

p-

d+

d-

s

f+

f-

Relativistic solution(Dirac eq.)

Non-relativistic solution (Schrodinger eq. )

Page 74: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

EDM in molecule

1. EDM of elementary particle and CP violation

2. What is measured as the prove of EDM in atoms or molecules

3. How to measure it

4. Why theoretical work is important

5. Formula of theoretical work

6.

Page 75: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

EDM and P/T violationIf non-zero EDM exists in an elementary particle,

there must be P and T symmetry violation!(Purcell, Ramsey, 1950)

spinEDM d

spin

EDM -dspin

EDM -d

Time reversalTime reversal((t t --t)t)

Parity reversalParity reversal((r r --r)r)

T-symmetry breakingCP symmetry breaking via CPT theorem

EDM measurement may improve Kobayashi-Masukawa theorem and explain the disappearance of anti-particles in the present universe .

Page 76: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Source of EDM in atoms or molecules

There may be various source for EDM in atoms or molecules.Here we only consider open shell systems and assume that molecular EDM comes from only electron EDM to obtain upper limit of de.

electron-quark

electron EDM

quark EDM

quark-quark

Page 77: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

History of e-EDM

YbF

Molecules!

Page 78: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

What is observed and calculated for e-EDM?

Atomic or Molecular Optics

Observation of the total interaction

Relativistic quantum chemistryCalculation of effective

electric field, Eeff

Particle PhysicsPrediction of de

CP violation?

0int

0m

iimed E

Interaction energy Interaction energy of Electron EDM of Electron EDM with internal electric field of molecule with internal electric field of molecule

Collaboration of three

different fields!

Page 79: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Electron EDM interacts with Electric field

e-

spinEDM de

Electric field E

Interaction energy = Eσ ed

q indicates spin direction.

If Electric field is large, interaction energy is large and easy to be measured.

Page 80: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Electron EDM interacts with Electric field

e-

spinEDM de

Electric field E

Interaction energy = i

N

iiiie

e

d

1

If we apply external magnetic field, electron spin and e-EDM becomes parallel to B. If we apply external electric field parallel or antiparallel to B, then the interaction becomes maximum.

In atoms or molecules there are a number of electrons.

Bmagnetic field

e-

spinEDM de

e-

spinEDM de

Page 81: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Electron EDM interacts with Electric field

e-

spinEDM de

Internal Electric field EInternal Electric field E

Effective electric field

eN

iiieffE

1

internalEσ

We need to know effective electric field from quantum chemistry calculations to elucidate de itself from experiments.

In polar molecules, internal electric field is already there.

Bmagnetic field

e-

spinEDM de

e-

spinEDM de

Yb

F

Page 82: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

External and internal electric field

F

Yb+q

-qEext

External electric field is necessary to align polar molecules. The largest internal electric fields may be along with the molecular axis. Furthermore, we apply a magnetic field with parallel or anti-parallel to the electric field, such that the interaction between e-EDM and Eint becomes large.

Eext

B-

B+

+

-

Page 83: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Effective electric field

Effective electric field will be the internal electric field in limit. The internal electric field can be obtained by ab initio calculations.

YbF experiment in 2002 Theoretical estimation:26GV/cm in YbF

The form of the curve is polarization of rigid rotator. is the direction of molecule axis.

Page 84: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

YbF experiment in 2002

A

F=1

A+q0

(F,MF)=(1,+1),(1,-1)

(1,0)

F=0

A+q1

(1,+1)

(1,-1)(1,0)

qqz

A+q1-qz

(0,0)

Without external field

With E (Stark shift) With E and B(Stark & Zeeman shift)

Consider YbF electronic ground state 2qv(vibrational)=0, N(rotational)=0J=1/2 (electron spin), I=1/2(nuclear spin) => F(total spin) =0 or 1

Page 85: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

YbF experiment in 2002

(1,+1)

(1,-1)(1,0)

qqz

A+q1-qz

(0,0)

With E and B(Stark & Zeeman shift)

TBd Beffez E 22

Interaction of electron EDM and effective electric field is spin-dependent and can appear with Zeeman shift. If we apply E and B in same direction and opposite direction, the two types of energy shift of 2qz is differently observed.

Page 86: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

F

Yb+q

-q V=440m/s

Yb(metal)+AlF3(liquid)1500K

Formation of YbF molecule

Detection of F=0 state(Fluorescence)

(1,+1)

(1,-1)qqz

z 2cosCoherent superposition

1,1211,1

21

Collect F=0 stateby some lasers

Equipment

Page 87: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Result

Eext=8.3kV/cm

z 2cos

ParallelUntiparallel

Page 88: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

The upper limit of de

ecmd state26102.32.0

J. J. Hudson, B. E. Sauer, M. R. Tarbutt, and E.A. Hinds, PRL, 89,023003,2002

“Improved measurement of the shape of the electron”J. J. Hudson, D. M. Kara, I. J. Smallman, B. E. Sauer, M. R. Tarbutt & E. A. Hinds, NATURE , 494 , VOL 473 ,2011

ecmd syststate28105.12.54.2

The latest report about YbF molecule

Page 89: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Form of Eeff• We cannot measure Eeff but can calculate it.

• Eeff appears only in relativistic frame work.

elecelec nuc N

ji ji

N

i

N

A Ai

AiDC

ZβmcpcHrrRr

1ˆ 2

Multi-electronic Dirac-Coulomb Hamiltonian

Nuclear attraction Electron repulsionKinetic and relativistic correction

DC

N

iiDCeff

elec

E intE

Eigenfunction of Dirac-Coulomb Hamiltonian, four component!

Expectation value of internal-electric-field projected into spin axis multiplied by beta matrix, coming from relativistic correction.

2222

2222

1001

S

S

L

L

DC

Page 90: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Internal electric field Eint

Mostly, it comes from nuclear attraction potentials.

rZrV

FYb

(Point charge nucleus model)

e-

rVE int

“e” is unit in atomic unit.

-Eint is the tangent of potentialtangent of potential.

Electrons close to heavy nucleus feel large electric field.

Electric potential in molecule

z axis

Page 91: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Parity symmetric orbital cannot have Eeff

Yb

elec

elecelec

elec

elec

elecelec

N

iNiNDC

N

N

iNDCiNDCeff

drdrdrrrr

rddrdrrrrrrrE

...,...,,

...,...,,,...,,

21int0

21

2121int0

21

E

E

Ex. 1s orbitalq(x)=q(-x)EExx ((xx) =) =-- EExx ((--x)x)x axis

q(x) Ex (x) + q(-x) (- Ex (-x)) = 0

Atom without external field

Eeff is zero.

Electron density

Page 92: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Parity symmetric orbital cannot have Eeff

Yb

elec

elecelec

elec

elec

elecelec

N

iNiNDC

N

N

iNDCiNDCeff

drdrdrrrr

rddrdrrrrrrrE

...,...,,

...,...,,,...,,

21int0

21

2121int0

21

E

E

q(x)=q(-x)EExx ((xx) =) =-- EExx ((--x)x)

x axis

q(x) Ex (x) + q(-x) (- Ex (-x)) = 0

Homo diatomic molecule

Eeff is zero.

Electron density

Yb

Center of inversion

Page 93: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Parity symmetric orbital cannot have Eeff

Yb

elec

elecelec

elec

elec

elecelec

N

iNiNDC

N

N

iNDCiNDCeff

drdrdrrrr

rddrdrrrrrrrE

...,...,,

...,...,,,...,,

21int0

21

2121int0

21

E

E

q(x) q(-x)EExx ((xx) ) --EExx ((--x)x)

x axis

Hetero diatomic molecule

Both density and electric field is not symmetric.Eeff is non zero.

Electron density

F

No center of inversion

Page 94: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Effective Hamiltonian of Eeff

25

int

2ˆ,

ˆ

pcediH

ed

EdH

eDC

e

eEDM

elecN

iDCDCDCEDMDC

e

peciH

d2

52ˆ1

Si

Li

cmpi

cmpi pcpic 242

54 Re42

SSOMO

LSOMO

N

i

Si

LiDCROHFeff

pc

pcEelec

2

2

Re4

Re4|

By B. P. Das

One-electron molecular orbital

Kramers-paired orbitals are cancelled in each other due to the spin projection of the electric field. Singly occupied orbital determines the nature of ESingly occupied orbital determines the nature of Eeffeff at the HF level. at the HF level.

Page 95: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Method Ref Eeff GV/cmQuasi-relativisticSemi-empirical Kozlov, 1997 26.1 GRECP-RASSCF Titov et al. 1997 18.8 GRECP-RASSCF-EO Mosyagin et al. 1998 24.9 GRECP-MRCI-SOCO Meyer et al. 2006 43.04-component DiracDHF+CP Quiney et al. 1998 24.8 UDF (unpaired electron) Parpia, 1998 19.9 UDF (all electrons) Parpia, 1998 24.9 DF Nayak et al. 2006 19.9 RASCI Nayak et al. 2006 22.5 MBPT(2) Nayak et al. 2007 21.6 DHF (Faegri’s contracted basis) This work 16.7DHF (uncontracted s basis) This work 17.0

Comparison of the previous works inYbF

Page 96: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Results at the Dirac-Coulomb-ROHF level

Eeff(GV/cm)

PDM(Debye)

YbF abe 16.7 4.20Meyer 24.7 3.55

BaF abe 5.8 4.21Meyer 7.4 3.51

HgF abe 79.3 4.98

Meyer 99 4.14

PbF abe -40.5 4.42Meyer -29 3.38

Eeff(GV/cm)

PDM(Debye)

YbSr+ abe 3.1 6.56Meyer -11.3 5.1

YbBa+ abe 0.7 4.50Meyer 1.2 5.1

YbRb abe 0.3 0.61

Meyer -0.7 0.21

YbCs abe 0.2 0.77Meyer 0.54 0.24

We need to beyond the Hartree-Fock level to get more reliable results. Coupled Cluster method

Faegri’s 4cmp-basis set (valence triple zeta)

Meyer et al: GRECP + MRCI + SOCI, Electric field of two nuclei and a lot of approximations… (50 % error contains)

Page 97: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Coupled Cluster methodOne of the most accurate methods to take into account

electron correlation within single reference theory

HFN EHH

HFHFHFHF EH

HFHFN TETH

expexp

321 TTTT : N-electron excitation operator

HFHFexact

TTT

2

ˆˆ1ˆexp2

exactexact EH ˆ

EElectron correlation energy

NT

HFHFN ETHT

expexp

occivira

iaoccivira

HFaaiatia

iatT,

1,

11 ,,ˆ t1, t2, … coefficients are the parameters to be obtained.

Page 98: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Coupled Cluster method

CN

NNNN

N

TH

TTTTHTTHTHH

THT

exp

,,,,!41...,,

!21,

expexp

0exp HFCNai TH

0exp HFCNabij TH

ETH HFCNHF exp

21 TTT

The above exponential expansion is terminate after four commutations because HN is at most two-electron operator.

means collect only connected terms which provide non-zero values.

CN TH exp

Coupled Cluster singles and doubles (CCSD) equations

abij

ai One-electron excited determinant

Two-electron excited determinant

... (1)

... (2)

Page 99: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

CCSD amplitude equations

CLK

ACKL

KLIC

DCK

CDIK

AKCD

CK

CK

AKIC

CK

CI

AK

ACIK

KC

K

AK

KI

C

CI

AC

CK

CI

AK

KC

AI

VVTV

TTTHTHTHTTFF

,,,

,,

0

2

0,,

CK

BK

CJ

AKIC

CK

CBKJ

AKICABIJ

DC

CDIJ

ABCD

LK

ABKL

KLIJ

C

CJ

ABIC

K

BAJK

KIIJ

K

BK

ABIJ

C

CBIJ

ACAB

ABIJ

TTVTHPPBA

TVTGPTVTGPV

Term notation of DIRAC08 RELCCSD from L. Vischer’s JCP paper

... (1)

... (2)

Non linear equations of T1 and T2, iteratively to be solved.

BAJI

ABIJ

IJAB

AI

AI

IACCSD VTFEE

,,

Page 100: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Problem in coupled cluster method for expectation value

For expectation value, CC method do not terminate in expansion. (Note that not inverse but dagger in bra part.)

HFTTTTHF

HFTTOTTHF

ON

N

2

ˆˆ12

ˆˆ1

2

ˆˆ1ˆ2

ˆˆ1

22

22

We need to use more complicated methodto get expectation value.We can calculate expectation value by solvingLambda equation, but it requires another effort.(Both programming and computational time)

Page 101: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Our approximation for expectation valueExpand the exponential operator in the Taylor seriesand truncate them only to the linear term for CCSD.

CN

CN

N

N

HFTTOTTHF

HFTTOTTHF

HFTTTTHF

HFTTOTTHF

O

2121

22

22

22

ˆˆ1ˆˆˆ1

2

ˆˆ1ˆ2

ˆˆ1

2

ˆˆ12

ˆˆ1

2ˆˆ1ˆ

2ˆˆ1

HFN OOO ˆˆ Normal order operatorNormal order operator

We can easily calculate this value using t1 and t2 amplitudes obtained from CCSD.

Page 102: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Our contracted basis sets• We usually use contracted basis sets for molecules in non-

relativistic case. (6-31G, cc-pvnZ, ANO, etc)

• In the 4-component Dirac case, contracted basis sets sometimes cause problems so called “variational collapse” (converge to extremely low energy or not converge due to the contamination of negative energy levels).

• However, if we use the two-component spinor basis scheme used in UTChem, we can avoid the problem and keep the concept of LCAO.

• Contracted basis set is more compact and faster in calculation than the primitive basis sets. Primitive basis set cannot be considered as full space in CCSD calculation.

Page 103: Molecular orbital theory and e-EDM in moleculesbijaya/Minori-lect.pdf · Schrödinger equation of Hydrogen atom Three integers come up when solving Schrödinger equation of H atom

Contracted basis set functionsDyall-QZ-c basis S 1s 2s 3s 4s 5s 6s6.5973426E+07 9.9782180E-05 -3.7200758E-05 1.7519609E-05 8.5062625E-06 3.2603668E-06 -8.3449817E-071.7573042E+07 2.3885301E-04 -8.9322205E-05 4.2086226E-05 2.0436349E-05 7.8332122E-06 -2.0049375E-066.0368629E+06 4.8228463E-04 -1.8095458E-04 8.5305558E-05 4.1427940E-05 1.5879797E-05 -4.0644893E-062.3148616E+06 8.8873685E-04 -3.3516266E-04 1.5812708E-04 7.6807417E-05 2.9441998E-05 -7.5358548E-069.7498001E+05 1.6115692E-03 -6.1126323E-04 2.8865029E-04 1.4023603E-04 5.3759158E-05 -1.3759946E-054.3572342E+05 2.8710341E-03 -1.0971913E-03 5.1870929E-04 2.5207492E-04 9.6635219E-05 -2.4734770E-052.0470199E+05 5.1348039E-03 -1.9786885E-03 9.3667476E-04 4.5532856E-04 1.7457384E-04 -4.4683531E-059.9654250E+04 9.2072616E-03 -3.5840701E-03 1.6992363E-03 8.2632136E-04 3.1681877E-04 -8.1094980E-054.9983316E+04 1.6583606E-02 -6.5322387E-03 3.1029055E-03 1.5095694E-03 5.7888801E-04 -1.4817268E-042.5663485E+04 2.9818647E-02 -1.1931486E-02 5.6815266E-03 2.7657042E-03 1.0606081E-03 -2.7149014E-041.3440699E+04 5.2950673E-02 -2.1662469E-02 1.0353665E-02 5.0443789E-03 1.9350958E-03 -4.9532159E-047.1598929E+03 9.0977035E-02 -3.8543746E-02 1.8528281E-02 9.0395936E-03 3.4681500E-03 -8.8782782E-043.8753556E+03 1.4628804E-01 -6.5598978E-02 3.1847069E-02 1.5573611E-02 5.9794889E-03 -1.5306719E-032.1307057E+03 2.0889813E-01 -1.0286939E-01 5.0763430E-02 2.4921791E-02 9.5740825E-03 -2.4513911E-031.1898903E+03 2.4396201E-01 -1.3823205E-01 7.0048345E-02 3.4607750E-02 1.3320170E-02 -3.4104986E-036.7429769E+02 2.0474701E-01 -1.3342031E-01 6.9688307E-02 3.4691717E-02 1.3362843E-02 -3.4233136E-033.8724214E+02 1.0102651E-01 -2.4179884E-02 8.1792671E-03 3.5358781E-03 1.3346475E-03 -3.3860593E-042.2481397E+02 2.1298438E-02 2.1261417E-01 -1.5951971E-01 -8.6463521E-02 -3.4004530E-02 8.7246883E-031.3362161E+02 1.3981505E-03 4.1121363E-01 -3.7713017E-01 -2.1585010E-01 -8.5749185E-02 2.2051823E-028.1281158E+01 4.1116786E-05 3.5057833E-01 -4.0182068E-01 -2.4250758E-01 -9.7776272E-02 2.5149688E-025.0939803E+01 3.8127887E-05 1.4856492E-01 -1.0447585E-01 -6.8770856E-02 -2.8918209E-02 7.5361505E-033.2280526E+01 -1.0441931E-04 2.9528209E-02 4.0069785E-01 3.6353582E-01 1.6166297E-01 -4.2214557E-022.0394685E+01 3.6942048E-05 1.8089816E-03 6.1447118E-01 7.4823240E-01 3.5515598E-01 -9.3081510E-021.2503244E+01 -3.2526750E-05 3.5775229E-04 3.2470347E-01 3.7866373E-01 1.6908482E-01 -4.4203642E-027.2874456E+00 2.4471759E-05 -3.1026960E-04 5.4055539E-02 -4.6352619E-01 -2.8413146E-01 7.6523038E-024.3210001E+00 -1.1535675E-05 3.3408769E-05 2.2180494E-03 -7.3973061E-01 -5.9688417E-01 1.6916103E-012.5234051E+00 8.3346020E-06 -7.0668008E-05 1.2025946E-03 -3.2042059E-01 -3.8288855E-01 1.1465921E-011.4175240E+00 -4.8775188E-06 3.8350509E-05 -2.7428342E-04 -3.8335074E-02 2.2717730E-01 -7.9496271E-027.9157400E-01 2.7643534E-06 -1.7666327E-05 9.1058439E-05 -1.4535011E-03 6.2283403E-01 -2.2484198E-014.4198499E-01 -1.7465836E-06 1.3620169E-05 -9.8219827E-05 -7.9721646E-04 4.5570588E-01 -2.7116462E-012.4345371E-01 8.5919476E-07 -6.0619634E-06 3.2241392E-05 -6.7667385E-05 1.0609629E-01 -1.5553717E-011.1878413E-01 -4.2231693E-07 3.0886469E-06 -1.6573828E-05 3.8028070E-05 5.1623573E-03 1.8463795E-016.1739139E-02 2.3280153E-07 -1.6835017E-06 1.4079000E-05 2.1992554E-04 3.9420751E-03 5.2053680E-013.1922684E-02 -9.6968198E-08 7.1602848E-07 -3.7927686E-07 1.6873698E-04 3.2883261E-03 4.4423560E-011.6420495E-02 2.3449273E-08 -1.6889708E-07 1.6939352E-06 3.5436438E-05 6.4944623E-04 8.6473321E-02

exponential coefficients

contraction contraction coefficientscoefficients

quadruplequadruplezetazeta