Breit-Rebi type correction for large hyperfine couplings?

[BIGMOKO]

Hello all,

I am slightly new to the software and I am looking to introduce a correction to my simulated 51V spectra.

My spectral simulations are fairly good representations of my experimental data, except they do not reproduce the unequal spacings between hyperfine lines. At lower magnetic field strength, the hyperfine lines are closer together, and at higher magnetic field strength they are farther apart.

Looking through textbooks and papers, the explanation i have found for this phenomenon is Second-order effects that arise from the large Hyperfine coupling values that vanadium tends to produce. These sources also say they can be corrected via second order perturbation equations or the Breit-Rebi equation.

My question is does EasySpin have some sort of function or parameter I can use to achieve this?
I have tried playing with the Opt.Method = 'perturb2', but that doesn't seem to account for my experimental observations.
If Easyspin cannot do this, how could I go about doing this?

Thanks in advance, and Happy New Year!

[Stefan Stoll]

EasySpin takes this into account, as long as you use Opt.Method='matrix' (exact matrix diagonalization) or Opt.Method=perturb2`' (second-order perturbation theory).

Here's a brief example:

Code: Select all

clear

Sys.Nucs = '51V';
Sys.A = 300;
Sys.g = 2;
Sys.lwpp = 1;

Exp.Range = [0 400];
Exp.mwFreq = 3;

Opt.Method = 'matrix';
[B,spc0] = pepper(Sys,Exp,Opt);

Opt.Method = 'perturb2';
[B,spc2] = pepper(Sys,Exp,Opt);

plot(B,spc0,B,spc2);
legend('matrix','perturb2');