annakater
Dear Topas users,
is there a way to define size broadening by integral breadth?
There is a macro in the manual called LVol_FWHM_CS_G_L, but this reports the integral breadth (IB) calculated after a refinement.
I was hoping to use a formula based on IB instead of lor_fwhm for introducing broadening in the pattern, while keeping the fundamental parameter approach.
Any ideas would be greatly appreciated.
Thanks,
Anna
johnsoevans
Anna,
I'm not sure exactly what you want to do. One piece of generic advice (sorry if obvious). Have you looked in topas.log to see what the lvol macro gets expanded to? Does this give you any tips?
e.g. a line like:
LVol_FWHM_CS_G_L(1, 2.78385`_0.00000, 0.89, 3.89147`_0.00000, !csgc, 10000, cslc, 4.37199`_2480.40428_LIMIT_MIN_0.3)
gets expanded to the equations:
prm = 1 / Voigt_Integral_Breadth_GL(1/!csgc, 1/cslc); : 5.37747`_0.00000 prm = 0.89 / Voigt_FWHM_GL(1/!csgc, 1/cslc); : 7.51616`_0.00000 prm !csgc 10000 gauss_fwhm = 0.1 57.2957795130823 Lam / (Cos(Th) (!csgc)); prm cslc 8.44398`_8761.55793_LIMIT_MIN_0.3 min .3 max 10000 lor_fwhm = 0.1 57.2957795130823 Lam / (Cos(Th) (cslc));
John
annakater
John,
thanks for your answer.
the macro Voigt_Integral_Breadth_GL(1/csgc, 1/cslc) does not introduce any crystallite size broadening. The parameters csgc and cslc are refined from lor_fwhm and gauss_fwhm.
If I define csgs and cslc as user-defined parameters and use Voigt_Integral_Breadth_GL, the parameters are not refined, they keep their initial values. I am looking for a function to introduce broadening by using integral breadth (peak area/peak maximum) instead of lor_fwhm.
By the way, I just noticed the value 57.2957795130823 in all _fwhm formulas, what does this correspond to?
Anna
johnsoevans
Anna,
I'm not aware of how to do this directly. My understanding is that integral breadths are extracted from peak shape essentially after refinement. Was just suggesting that you could extract them then use in other equations.
57.29 is just 360/(2*pi) to convert degrees to radians.
Sorry not more helpful.
John
annakater
Its still nice to get a reply anyway :)
Thanks!