EasySpin forum

Hi all

I am trying to simulate the X-band 279 K spectrum for copper acetate which results from the di-nuclear copper acetate's antiferromagnetic coupling. How can I go about doing this? I will attach the research paper this comes from here:
https://pmc.ncbi.nlm.nih.gov/articles/PMC10572876/

I assume that this example script from the easy spin website is a good starting point due to the coupled spins:

% Two coupled electrons
%==========================================================================
clear, clf

% Two-electron system, both electrons with rhombic g tensor
Sys.S = [1/2 1/2];
Sys.g = [2 2.05 2.1; 2.2 2.25 2.3];
Sys.lwpp = 1;

% Electron-electron couplings
Sys.J = 50; % isotropic coupling, in MHz
Sys.dip = 100; % axial dipolar coupling, in MHz

% X band conditions
Exp.mwFreq = 9.5; % GHz
Exp.Range = [280 350]; % mT

pepper(Sys,Exp);

title('Two dipolar coupled orthorhombic S=1/2');

The research paper also provides the zero splitting parameters D and E So I assume incorporating these into the script will be necessary as well.

You are wrong. According to the publication, you should use the S=1 approach instead of two coupled S1=1/2 and S2=1/2 spins.

You can either employ the "giant spin" approximation (S = 1 with use of D and E) as in the paper you cite, or the full spin exchange Hamiltonian (S1 = S2 = 1/2), in which case the "D" and "E" of your triplet state are the result of the dipolar-induced anisotropy. In that latter case, you also need to properly define the gFrames (according to the crystal structure as a first approximation).

Briefly, it is an "either/or" choice.