Reporting Full Voight FWHM

babaryk

Dear TOPAS users,

I'm fitting a sychrotron data with a full Voight profile function as suggested here:
https://community.dur.ac.uk/john.evans/topas_workshop/tutorial_synchy2o3.htm,
for instance,

prm pr1 0.00676` min 0
prm pr2 0.00682` min 0
prm pr3 0.00731` min 0
prm pr4 0.00809` min 0

lor_fwhm = pr1 Tan(Th) + pr2/Cos(Th) ;
gauss_fwhm = pr3 Tan(Th) + pr4/Cos(Th) ;

As Wiki tells, FWHM of voightians can be approximated using the expression:
fwhm_voight = 0.5346 fwhm_lor + Sqrt(0.2166 * fwhm_lor ^2 +fwhm_gauss ^2)

Has anybody a clue how to get values in an output file?

Cheers,
Artem

alancoelho

try
str
...
prm fwhm_lor = pr1 Tan(Th) + pr2/Cos(Th) ;
prm fwhm_gauss = pr3 Tan(Th) + pr4/Cos(Th);
lor_fwhm = fwhm_lor;
gauss_fwhm = fwhm_gauss;
phase_out file.txt append load out_record out_fmt out_eqn
{
"%4.0f" = H;
"%4.0f" = K;
"%4.0f" = L;
"%11.5f\n" = 0.5346 fwhm_lor + Sqrt(0.2166 * fwhm_lor ^2 +fwhm_gauss ^2);
}

The output will be contained in the file file.txt.

babaryk

Dear Alan,

It still goes with an error:

"Uninitialized_Variable in equation: fwhm_lor"

for

prm pr1 0.05452`
prm pr2 0.00118`
prm pr3 0.00000`
prm pr4 0.00379`

lor_fwhm = pr1 Tan(Th) + pr2/Cos(Th);
gauss_fwhm = pr3 Tan(Th) + pr4/Cos(Th);
lor_fwhm = fwhm_lor;
gauss_fwhm = fwhm_gauss;

phase_name "..."
space_group "..."
load hkl_m_d_th2 I
.....

out file
Out_String("loop_\n")
Out_String(" _refln_index_h\n")
Out_String(" _refln_index_k\n")
Out_String(" _refln_index_l\n")
Out_String(" _refln_Voigt_FWHM\n")
Out_String(" _refln_F_squared_meas\n")
phase_out file append load out_record out_fmt out_eqn
{
"%4.0f" = H;
"%4.0f" = K;
"%4.0f" = L;
"%15.4f\n" = 0.5346 fwhm_lor + Sqrt(0.2166 fwhm_lor ^2 + fwhm_gauss ^2);
"%15.4f\n" = I_no_scale_pks / M;
}

Thanks,
Artem

alancoelho

Hi Artem

You have:

lor_fwhm = pr1 Tan(Th) + pr2/Cos(Th);
gauss_fwhm = pr3 Tan(Th) + pr4/Cos(Th);
lor_fwhm = fwhm_lor;
gauss_fwhm = fwhm_gauss;

You have not defined fwhm_lor using prm; ie. use:

prm fwhm_lor = pr1 Tan(Th) + pr2/Cos(Th) ;
prm fwhm_gauss = pr3 Tan(Th) + pr4/Cos(Th);
lor_fwhm = fwhm_lor;
gauss_fwhm = fwhm_gauss;

If you get stuck then e-mail me your INP and data file.
cheers
alan

babaryk

Dear Alan,

It works. Thank you very much!

Cheers,
Artem

yuedeng

Hi,

if i am using a str and want focus on one hkl peak, ie. (111) peak, is there an easy way?

The following script generate a whole list of all hkl peaks.

AlanCoelho:1447683622 wrote Hi Artem

You have:

lor_fwhm = pr1 Tan(Th) + pr2/Cos(Th);
gauss_fwhm = pr3 Tan(Th) + pr4/Cos(Th);
lor_fwhm = fwhm_lor;
gauss_fwhm = fwhm_gauss;

You have not defined fwhm_lor using prm; ie. use:

prm fwhm_lor = pr1 Tan(Th) + pr2/Cos(Th) ;
prm fwhm_gauss = pr3 Tan(Th) + pr4/Cos(Th);
lor_fwhm = fwhm_lor;
gauss_fwhm = fwhm_gauss;

If you get stuck then e-mail me your INP and data file.
cheers
alan