what is fullprof? -...

What’s FullProf ? T.R. (Mexico 21-25 June 2004)

What is What is FullProfFullProf ??

Juan Rodríguez-CarvajalLaboratoire Léon Brillouin (CEA-CNRS),

Centre d’Etudes de Saclay91191 Gif sur Yvette Cedex (France)

Email: [email protected]

Thierry RoisnelLaboratoire de Chimie du Solide et Inorganique Moléculaire

Université de Rennes 1 (France)


What’s FullProf ?• A program for :

Simulation of powder diffraction patternsPattern decomposition integrated intensities Structure refinementPowder and single crystal data

• Crystal and magnetic structures

• Multiple data sets: simultaneous treatment of severalpowder diffraction patterns (CW X-rays & neutrons, Energy dispersive X-rays, TOF neutron diffraction)

• Combined treatment of single crystal and powder data

• Structure determination capabilities: simulated annealing on integrated intensity data


Features of FullProf• Choice of peak shape for each phase• Background: fixed, refinable points, polynomial function,

Fourier series …• Multi phase (up to 16 phases)• Preferential orientation• Absorption correction for cylinder and flat plate sample

shape• hkl dependence FWHM for strain and size effects• Quantitative analysis• Atomic distances and angles calculations• Rigid Body description• …


A few words of history …(1)

• Origins: DBW program, 1981 in Barcelona (thanks to Ray Young)

• Reorganization towards a structured programming within the FORTRAN 77 language, corrections of bugs, different ways of calculating R-factors, etc. Barcelona/Grenoble (1982-1987)

• Introduction of magnetic scattering, anisotropic broadening, profile matching (now known as Le Bail method), rigid bodies1988-1992, Institute Laue-Langevin, Grenoble. The name FullProf is adopted in 1990"FULLPROF: A Program for Rietveld Refinement and Pattern Matching Analysis"J. Rodríguez-CarvajalPowder Diffraction, Satellite meeting of the XV congress of the International Union of Crystallography, Toulouse 16-19 July (1990)


A few words of history …(2)

• Improvements of magnetic scattering options, new peak shapes,single crystal and integrated intensities options, ...Distribution by anonymous ftp in 1993. LLB, Orsay (near Paris)

• Introduction of a rudimentary option for handling Time of Flight neutron powder diffraction data in 1996.

• WinPLOTR and Windows version of FullProf, distribution viathe LLB Web site. Progressive conversion to Fortran 90 style and conventions (1998).

• Complete reorganization of the code within the new Fortran 90language. Programmed in the subset ELF90. Multiple data sets,TOF improvements (Barcelona, Argonne, Orsay, 1999 …)


FullProf Web site:http://www-llb.cea.fr/fullweb/fp2k/fp2k.htm

or

ftp://ftp.cea.fr/pub/llb/divers/

Basireps

Rietveld-Exercises

fullprof.2k

fullprof_examples

fullprof_exercises

tutorials

winplotr


New FullProf Web site:

http://valmap.dfis.ull.es/fullprof/

under construction …


FullProf

Outputfiles,Plot

diffr. patterns

Minimal input:Input control file (extension ‘ .pcr ’): PCR-fileModel, crystallographic/magnetic information

PCR file

DAT file(s)Eventually, experimental data

How works FullProf


Many variables and options Complex to handlePCR file

Format depending on the instrument, usually simpleDAT file(s)

Hint: copy an existing (working) PCR-file and modify it for the user case, or...

USE the new GUI: EdPCR

The PCR file: steep learning curve


Output files created by FullProf

.OUT output file of the calculation: details of refinement, correlation matrix, intensities, FWHM, 2θH, …

.SUM summary of the .OUT file

.BAC background file

.PRF Yobs, Ycalc, Yobs-Ycalc, 2θΗ

.RPA summary of refined parameters

.SYM list of symmetry operators

.FOU hkl and F2 list for Fourier maps

.HKL complete list of reflections for each phase

.MIC microstructural information


--------------------------------------------------------------------------In this file new features, as well as discovered bugs, of FullProf.2kare periodically documented. For details consult the manual of FullProf.From 10 May 2003, comments on the programs constituting the FullProf suiteare also provided.

Juan Rodriguez-Carvajal (Laboratoire Leon Brillouin, Saclay)--------------------------------------------------------------------------

---------------28 July 2003

---------------- An updated version of FullProf.2k is now available.

. . . . . . . . .- Some changes have been introduced for treating the background:

(1) The polynomial background of 12 coefficients, for constant wavelength case, has beenchanged so that the last three coefficients correspond to inverse powers of 2theta.. . . . . . .

(2) Now there is the possibility to include several previously calculated profiles ascontributing, through a linear combination, to the background of a powder diffractionpattern. The individual profiles are read in input files named "filedat_n.bac". Where"filedat" is the code of the data file corresponding to a diffraction pattern and theindex "n" is the number of the contributing profile. The additional contribution tothe background is calculated as:

Last minute changes in FullProfDocumented in “fp2k.inf”


Least squares minimization technique local minima

Some prescriptions to avoid divergence of refinement:

Well knowledge of the diffractometer:

. First of all, determine the Instrumental Resolution Function (IRF): evolution of shape and FWHM versus scattering variable, for the diffractometer setup (monochromator adjusting, collimation slits …)

Use the best possible starting model:. Background parameters. Lattice constants

The Rietveld Method in practice (1)

Can be previously refined from whole pattern fitting


The Rietveld Method in practice (2)

In all cases, it is essential to plot frequently the calculated and experimental patterns: examination of the difference plot is a quick and efficient method to detect blunders in the model or in the input file which control the refinement process

Do not start by refining all parameters as the same time !

1- scale factor

2- + zero shift of detector, 1st background parameter and lattice parameters

3- + atomic positions, overall Debye-Waller factor

4- + PSF, asymmetry parameters

5- + atom occupancies (if required)

6- + individual isotropic thermal parameters

7- + additional background parameters

8- + instrumental or physical aberrations


No structural information (i.e. atomic positions) is needed, except space group and approximate cell parameters

* the scale factor is fixed (any particular value)* integrated intensities are free parameters and refined individually, using iteratively the Rietveld formula for getting the “observed”intensities: Starting from crudely estimated Ih(n=0), the new intensity at cycle (n+1) are calculated as:

Total-pattern fitting (profile matching)JBT=2

,( ) ( 1) . .obsi bi

h h i h calci i bi

y yI n I ny y

−= − Ω − ∑

•others parameters (cell parameters, zero shift, PSF, asymmetry …) are refined by the usual L.S. procedure

This whole profile fitting procedure leads to a list of integrated intensities: this method is thus a convenient first step (actually the best!) for structure determination from powder data.


Total-pattern fitting (profile matching)JBT=2

Important points:* all hkl reflections permitted by the space group are considered and included in the refinement, even if the reflections are not observed !

* in case of severe overlap of reflections and poor reliability starting parameters, it is wise to start with low angle reflections (without refining FWHM parameters) and progressively increase the angularrange.

Some recommendations:

* 1st refinement run (~10 cycles):

. IRF_n = 0 for each phase

. Number of refined parameters = 0

* if the 1st step is satisfactory (see plot) Least squares refined parameters: zeroshift, cell parameters, background …


Hint’s trick

Limited number of measured reflections:

* select refined parameters * fix some parameters to physically reasonable values

Start with standard profile parameters of your instrument

Examine carefully the difference pattern with a plotting program


FullProf examples: content of pcr_dat.zip

ftp://ftp.cea.fr/pub/llb/divers/fullprof_examples/pcr_dat.zipCrystallographic structures:

* conventional X-rays diffraction patternCeO2 ce*.*mixture of rutile and anatase: rutana.*Tb2BaCoO5(R.M. and profile matching) tbbaco.datPbSO4 pbsox.dat

* neutrons:PbSO4 pbso4.datY0.9Ca0.1Ba2Cu3O7 ybacud1a.dat

Magnetic structures:Ho2BaNiO5 hobk.datDyMn6Ge6 dy.dat

Strain refinement:La2NiO4 la.dat


FullProf refinement codewords

For each refined parameter, the codeword Cx is formed as:

Cx = sign(a) . (10p + abs(a))

p: ordinal number of the parameter x (1


Tutorials and documentation

Introduction to the program FullProfftp://ftp.cea.fr/pub/llb/divers/tutorials/fpjdn.ps

Structural Analysis from Powder Diffraction Data: the Rietveld Methodftp://ftp.cea.fr/pub/llb/divers/tutorials/jdn_97.pdf

FullProf user’s guide distributed with FullProffp2k.inf, FullProf.ins, fullprof_manual.pdf

Other PDF documents and exercises in ZIP files atftp://ftp.cea.fr/pub/llb/divers/Rietveld-Exercisesftp://ftp.cea.fr/pub/llb/divers/fullprof_exercisesftp://ftp.cea.fr/pub/llb/divers/fullprof_examples


Tutorials and documentation (Español)

Francisco Cruz Gandarilla y Mateo Jergelhttp://www.esfm.ipn.mx

⇓Postgrado

⇓Postgrado en C. de Materiales.

⇓Planta Docente.

⇓Cruz Gandarilla , Francisco.

⇓Aplicaciones de la difracción de Rayos- X.1.6


Acceso directo:

http://www.esfm.ipn.mx/sepi/poscmat/AplicacRayosX1.6

El curso se concibió de forma tal de que sus notas pudieran ser distribuidas de forma libre entre los estudiantes y que sirviera a todos aquellos que se inician en la difracción de rayos X en Ciencia de Materiales. Si algún docente se interesa en utilizar las mismas en sus cursos solo le rogamos enviar una carta de constancia a nombre de los profesores del curso.

Francisco Cruz

Mateo Jergel

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