EasySpin forum

Hello,

I am trying to simulate an EPR spectrum by using "esfit". I have two spins which are identical by symmetry. However, when I try to fit the spectrum, EasySpin varies independently the perpendicular components of the g-tensor of each spin. Is it possible to impose somehow inversion symmetry or use some constrains so, that the gx and gy of both centers are varied simultaneously and not independently?

Thanks

Use a user-defined fitting function, as explained here.

Thank you for your quick reply. I tried to use the function as described in the manual, but unfortunately I receive some errors. Could you please have a look at my input and tell me what I am doing wrong?

Many thanks in advance for your help!
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clear, clc, clf
[B,spc] = textread('exp.txt','%f %f');
function y = mymy(Sys,Exp,Opt)
ee = [0.0 0.0 0.0; 0.0 0.0 0.0; 0.0 0.0 -25000];
Sys.S = [1/2 1/2];
Sys.ee = [ee];
Sys.HStrain = [10 10 10];
Exp = struct('Temperature',5,'mwFreq',35,'Mode','perpendicular','Harmonic',1);
Opt = struct('nKnots',45);
fullSys = Sys;
fullSys.g = [Sys.g; Sys.g];
[x,y] = pepper(fullSys,Exp,Opt);
Sys.g = [0.15 19.0];
Vary.g = [0.1 0];
esfit('mymy',data,Sys,Vary,Exp);

Can you post your function mymy? In what you posted, it's not clear what is the function and what is the code that calls it.