PostConvNucs for 78 line spectrum

[FlorianJohannsen]

Hi,
I am trying to simulate the EPR spectrum of CTPO according to (https://doi.org/10.1016/0022-2364(84)90196-3).

"[...] assuming 12 equivalent methyl protons and 1 additional proton, where the additional proton coupling is about 2.5 times greater than the methyl proton couplings."

---

Sys.g=[2.0084 2.0061 2.0022];
Sys.Nucs='1H,1H,14N'
Sys.A=[2 2 2;5 5 5;15 15 110];
Sys.n=[12,1,1];
Sys.lwpp=[0 0.01];
Sys.tcorr=0.1e-9;
Sys.Exchange=0.1;
Exp.mwFreq=9.5;
CenterField=2piExp.mwFreq1e9hbar/(bmagnmean(Sys.g))1e3;
Exp.CenterSweep=[CenterField 10];
Exp.nPoints=10*1024;
Exp.Harmonic=0;

Opt.LiouvMethod='fast';
Opt.PostConvNucs=[1 2];

[field,spc]=chili(Sys,Exp,Opt);

figure
plot(field,spc)
xlim([field(1) field(end)])

---

There might be a bug using the option "PostConvNucs".

Error using chili
Opt.LiouvMethod='fast' does not work with this spin system.

Error in compisoloop

Error in chili

EasySpin works well with two nuclei, i.e. the twelve equivalent protons of the methyl groups can be treated with "PostConvNucs". Adding the additional proton of the pyrrolidine ring produces the error above. Changing "Opt.LiouvMethod" to "general" doesn't solve the issue.

How can I simulate the spectrum? I'm happy for any advice.

[Stefan Stoll]

Unfortunately, this doesn't work at the moment. Opt.LiouvMethod='fast' only works with up to two nuclei. Opt.LiouvMethod='general' currently does not support exchange (Sys.Exchange).

Looking at the paper, it appears that it might be sufficient to include the exchange only via its effect on the linewidth. A simulation with garlic should therefore be sufficient (and a lot faster):

Code: Select all

clear, clc

CTPO.g = [2.0084 2.0061 2.0022];
CTPO.Nucs = '1H,1H,14N';
CTPO.A = [2 2 2; 5 5 5; 15 15 110];  % MHz
CTPO.n = [12 1 1];

exchangeLineWidth = 0.4;  % MHz
CTPO.lwpp = [0 mhz2mt(exchangeLineWidth)];

Exp.mwFreq = 9.5;  % GHz
Exp.CenterSweep = [338 10];  % mT
Exp.nPoints = 10000;

[B,spc] = garlic(CTPO,Exp);
plot(B,spc)

[FlorianJohannsen]

Hello Stefan,
thanks for your message. Thats good advice.