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Dear colleagues

I want to simulate an EPR spectrum of a [NiCuNi] complex that is a (1-1/2-1) spin system. The ground state is S=3/2. The Ni(II) ions are very anisotropic and the local D tensors have not the same orientation. So I try to use Sys.DFrame instruction with the corresponding Euler angles but the Sys.DFrame instruction has no effect and the EPR spectrum remains the same with or without this instruction. As it was weird to me I tried on a more simple system [Ni-Ni] with one of the two local tensor disoriented with the following Euler angle [0 pi/2 0]. Even with this very simple case the Sys.DFrame instruction do not produce any change in the EPR Spectrum
By contrast if I calculate the rotation matrix and the disoriented tensor and enter both tensors I have a complete change of the EPR spectrum.
I am probably doing something wrong but I do not find my mistake

Thank tou for your help

Yves Journaux

PS : Code below
Sys.S=[1 1];
Sys.g=[2.2 ; 2.2];
D1=[0 0 8000]
D2=[0 0 8000]
DFrame1=[0,pi/2,0]
D_D=diag(D1)
R=erot(DFrame1)
D_M2=inv(R)*D_D*R

%Sys.D=[D_M2; D_D]
%Sys.D=[D_D;D_D]

Sys.D=[0 0 8000;0 0 8000]
Sys.DFrame=[0 pi/2 0;0 0 0]

Sys.ee=[200000]

Sys.lwpp = 10;


[H, I1]= pepper(Sys, Exp,SimOpt);
plot(H, I1,'b');
hold on ;

Please post a complete and self-contained script that illustrates the problem (plotting the two spectra simulated with the two different approaches on top of each other), so we can have a look.

Thank you for your answer
Finally I found why Sys.DFrame was not working; I did not clear all variables from the previous calculations. Actually I am not very familiar with Matlab, I generally use Mathematica software and apparently as in Mathematica Matalb keeps the values of the variables in memory even if you started a new calculation

regards