Shifting of the EPR spectra of cobalt complex

[anibhandari.91]

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I want to simulate EPR spectra of cobalt complex but the simulated spectra(red line) exceeding g value range and spectra did not match with the experimental one(Blue line). How can i solve this problem??
Code I am using
[B,spc] = textread('CO.txt','%f %f');
Sys1.g=[1.987 2.1084];
Sys1.lw=[2 0.5];
Sys1.Nucs='59Co';
Sys1.A=[70 50 65];
Sys1.nPoints=3750;
Exp1.nPoints=3750;
Exp1.Range=[300 360];
Exp1.mwFreq=9.4268
Opt.Method='hybrid';
plot(B, spc/max(spc), B, pepper(Sys1,Exp1,Opt)/max(pepper(Sys1,Exp1,Opt)));

Please suggest me suitable parameter to simulate this spectra. Thank you.

[nwili]

Either you think about how the parameters you have manifest in the spectrum, and change them accordingly (i.e., the hyperfine coupling), or you look into the esfit function.

[anibhandari.91]

Thank you nwili.
I have changed the hyperfine splitting constant(A) but the the simulated spectra(red line) does not exactly matches with the experimental one what parameter should I use so that spectra exactly matches with the experimental one or it is correct no need for further simulation.

[nwili]

This is science. I am not the authority to tell you whether this is correct or not. It looks reasonable, but I do not know the system. Two things you can still have a look at:
1) line width
2) baseline correction. The experimental spectrum shows some drift, which is not included in the simulation. either you do the background correction of the experimental spectra before, or you use the "rescale" function including baseline correction to adjust the simulated spectrum to the experimental one. Personally, I prefer the latter option, as it is more "honest" about the experimental data.

[Stefan Stoll]

Here is how I would go about it:
1. Make sure your experimental field axis and microwave frequency are accurately known.
2. Survey the literature for similar compounds and look at the EPR parameter (g and A) found there.
3. Start with a reasonable set of parameters based on the literature and simulate the spectrum. Vary each of them manually to see which parts of the spectrum is affected.
4. Using this insight, adjust the parameters manually to get a decent fit of a simulated spectrum to the experimental on.
5. Once your fit is close, use esfit to refine the parameters.

[anibhandari.91]

Thank you all.