EasySpin forum

Hello,
Greetings. I am very new to the easy spin software and MATLAB. I am facing some problem in simulation of EPR spectrum of Cu4Gd cluster (Frozen solution 5 K). Two copper(II) ion (both are five coordinated {O4N}) and a Gd(III) are bridged by mu3-hydroxo group and these three metal ions are occupied at the vertices of a triangle. There is an another triangle made by the remaining Cu(II) ion and Gd(III). The two triangles share a common vertice through a Gd(III) ion, thus two triangles are linked.
We have fitted the ChiT(T) data using two J model (Jcu-Gd = 0.9 cm-1 and JCu-cu = -3.9cm-1 in -2J Hamiltonian).

Using this information I am trying to simulate the EPR spectrum. The following are the input file that I have created and the Error message obtained are appended. Please suggest to how to rectify this mistake and how can I approach this problem?

Input:
Sys.S = [7/2, 1/2, 1/2, 1/2, 1/2];
Sys.J = [J12 J13 J14 J15 J23 J45];
Sys.Nucs = 'Cu, 14N';
Sys.A = [50 50 130; 20 20 40];
Sys.g = [2.01 2.01, 2.01; 1.99 1.99 2.3; 1.99 1.99 2.3; 1.99 1.99 2.3; 1.99 1.99 2.3];
Sys.D = [200 50 50 50 50];
J12 = -54000;
J13 = -54000;
J14 = -54000;
J15 = -54000;
J23 = 228000;
J45 = 228000;
Sys.lw = 2;
[B, spc] = eprload('Cu4Gd_5K_solution.DSC');
data = [B(:) spc(:)];
save('cugd_sim', 'data','-ascii');
Vary.lw = 0.3;
Vary.g = [0.01 0.02 0.02];
Exp.mwFreq = 9.379671;
Exp.Range = [700 1400];
esfit('pepper',spc,Sys,Vary,Exp);

Error message:
Error using pepper
Spin system field J has wrong size for the given spins.

Error in pepper

Error in esfit

Error in esfit_simplex

Error in esfit

Error while evaluating UIControl Callback

I am trying to upload the .DSC, .DTA or the excel sheets of the experimental EPR spectrum, but it states the error message "The extension DSC or DTA or xlsx is not allowed".

For 5 spins you have a total of 10 Jij interactions.

Try:

Hi
Upon inclusion of 10 Jij interactions, the programme says error in line 2 ie. "Sys.J = [J12 J13 J14 J15 J23 J24 J25 J34 J35 J45];"

Error message

Undefined function or variable 'J24'.

Error in Cu4Gd_trial (line 2)
Sys.J = [J12 J13 J14 J15 J23 J24 J25 J34 J35 J45];

ES cannot guess the values of the new variables. You need to define them explicitly.
E.g. J24 = 0, or just put zeros inline: Sys.J = [J12 J13 J14 J15 J23 0 0 0 0 J45].