Unexpected powder spectra after rotation of reference frames

[harrymickenzy]

Dear all,
I am performing some preliminary test to simulate spectra of an exchange-coupled pair of largely anisotropic effective doublets. The relevant hamiltonian is then H= B(g1*S1+g2S2)+JS1S2+S1DS2.
When simulating the powder spectrum with the code I include below I got two different patterns if I rotate the reference frames of all the anisotropic interactions in the same way (i.e. gFrame1=gFrame2=DFrame), see figure. I am sure I am missing something here, because in principle what I would like to do is a simple change of reference frame which should not affect the powder spectrum.
Any help would be welcome.

CODE: SELECT ALL
clear all
convfact=clight/1e4; %cm-1 to MHz

testaniso.S = [1/2 1/2]
testaniso.g = [4.16 1.52 1.08;4.16 1.52 1.08]; % g, for two electron spins
testaniso.J=-0.08*convfact;
testaniso.eeD =[-0.16 0.08 0.08]*convfact;
testaniso.lw=[10 10];
testaniso.HStrain=[700. 700. 700.];
Exp=struct('mwFreq',94.3,'nPoints',8192,'Range',[10 7500],'Temperature',10,'Harmonic',1); %campo in mT
Opt.nKnots=[91 3]
[B1,spec1] = pepper(testaniso,Exp,Opt);
figure('Name','Spectrum','NumberTitle','off');

[Stefan Stoll]

There might be an issue with the automatic symmetry determination. Please post a complete script that plots the two different spectra, and we will look into it. You can always bypass automatic symmetry determination by specifying Opt.Symmetry = 'Ci' or 'C1'.