effective spin-system and pseudonuclear effects with saffron

[lorenz]

Hi,

I would like to simulate orientation selective Hyscore on a lower kramers doublet (S=3/2) with saffron.
By using the effective rombic g-tensor values (with s'=1/2), the pseudo-nuclear Zeeman-tensor is not included. Is there a way to include this effect with saffron?
Or would it be better to calculate the real g-values + zerofield-splitting parameter from the effective g-values and run saffron with the whole S=3/2 spin-system.
In that case there should be no trouble with the pseudo-nuclear effects? Is this right?
Are there any limitation to the zerofield-splitting and electron Zeeman Hamitonian when using saffron, especially if the ZFS is much larger than the electron Zeeman?

Kind regards
lorenz

[Stefan Stoll]

I recommend running the simulation with S=3/2. It works for any size of the zero-field splitting. saffron diagonalizes the Hamiltonian without the superhyperfine nuclei to get energy levels and states which are then used to calculate orientation- and transition-selection factors. Just make sure to include Exp.mwFreq and Exp.ExciteWidth.

Unfortunately, there is no direct way in EasySpin to specify a pseudo-nuclear Zeeman term.

[lorenz]

Thank you very much for your answer.
If I understand your answer correctly, the effect of pseudonuclear zeeman tensor should be included if I use the total spin hamiltonian.
So the systematical error should be smaller instead of using the fictitious spin system.
Is this correct?

Kind regards
lorenz

[Stefan Stoll]

That's correct!

[lorenz]

Thanks a lot for your quick answer

[lorenz]

Dear easyspin team,

I've tried to simulate the follwowing Spin-System:
S=3/2; g=[2.00 2.03]; D=[1 0.053]*12.2*cm^-1, (This correspondes to a ficticous S'=1/2-System with: g'=[4.31 3.67 2.01]
I want to Simulate the Hyperfine couplings of two nulcei on the lower kramers doublet.
By computing the Spectra (3PESEEM and Hyscore) with saffron (S=3/2-System), there occous additional lines at higher frequnencies. I would not ecpect these frequencies by simulation with a ficticous Spin-System S'=1/2.
Are these the transitions of the higher Kramers doublet? Does saffron calculatetes all possible transitions between all possible Subhamiltionias? Or is always the asumption done, that only the lowest spin-state is populated?
If its so: Is it possible to force saffron to only one transition?

Kind regards
lorenz

[Stefan Stoll]

Please post a short self-contained script that demonstrates what you are describing.

[lorenz]

Dear Easyspin-Team,

here is my easyspin-input, its an example on g~2 in X-Band:

%Define Experiment 3PESEEM (ideal Pulses):
Exp.mwFreq=9.70;
Exp.Field=341.8;
Exp.T=0.4;
Exp.tau=0.13;
Exp.dt=0.020;
Exp.Sequence='3pESEEM';
Exp.ExciteWidth=1000/16; %Orientationselection ~60MHz
Exp.nPoints=1024;

%Define System1:
%real Spin System: S=3/2
Sys1.S=3/2;
Sys1.g=[2.00 2.03];
Sys1.D=[1 0.053]*12.2*10^4*3; %D=12.2cm^-1 E/D=0.053
Sys1.Nucs='13C,13C';
Sys1.A=[1.2 2.8 2.9;0.4 1.7 -1.5]; %real HFS

%Define System2:
%ficticous Spin-System S'=1/2
Sys2.S=1/2;
Sys2.g=[3.67 4.31 2.01];
Sys2.Nucs='13C,13C';
Sys2.A=[1.2*3.67/2 2.8*4.31/2 2.9;0.4*3.67/2 1.7*4.31/2 -1.5]; %HFS ficticous Ai'=Ai*g'i/g g~2


%Define Options:
Opt.nKnots=181;
Opt.TimeDomain=0;
Opt.Window='ham+';
Opt.ZeroFillfactor=2;

figure(1)
saffron(Sys1,Exp,Opt);
figure(2)
saffron(Sys2,Exp,Opt);


%The expected peaks look quite similar, but there appear additional peaks at 6,5MHz and 10MHz when I use the Full Hamiltonian.
%Might this be the upper Kramers doublet?
% Easyspin-Verion: 5.0.15
% Matlab-Version: 2013b
%
%Thanks you for your help

[lorenz]

Add:

I have alread checked both Spin-System with a simulated cw-Experiment ('pepper'), they look similar.

[lorenz]

Add:

I'm quit sure, that the additional peaks are due to the upper Kramers doublet.
If you add the follwoing spin-system:

%Define System3:
%ficticous Spin-System S'=1/2 upper doublet
Sys3.S=1/2;
Sys3.g=[0.34 0.32 6];
Sys3.Nucs='13C,13C';
Sys3.A=[1.2*0.34/2 2.8*0.32/2 2.9*6/2;0.4*0.32/2 1.7*0.34/2 -1.5*6/2]; %HFS ficticous Ai'=Ai*g'i/g g~2

%Define Options:
Opt.nKnots=181;
Opt.TimeDomain=0;
Opt.Window='ham+';
Opt.ZeroFillfactor=2;

figure(3)
saffron(Sys3,Exp,Opt);


By weighting the FFT-spectra of the lower and upper Kramers doublet, it looks similar to the data for the of the real S=3/2 Spin System.
So I think there is a significant mixure of the Levels.
How can I aviod this?
Is there a way to force saffron to lower initial state?
For example with the temperature for the inital density-matrix?

Kind regard
lorenz