3pESEEM

[Khalil]

Hi,
I am trying to simulate a 3pESEEM data. When using esfit it fits only the time domain of the 3pESEEM data and I was wondering if there is any way to use esfit to fit the frequency domain of the ESEEM data.
The second question that I do have is regarding the modulation depth in the ESEEM data. According the the ESEEM theory, the modualation depth depends on the number,n, and distances, ri, of nuclei coupled to the electron spin but when using saffron to simulate the time domain ESEEM data the modulation depth seems not changing with the number of nuclei (Sys.n). It's all the time showing the same depth depth regardless how many nuclei you put in. I used the script shown below. Any suggetions or comments??
Regards
===========
[x,y,pars] = eprload (file_1);
spec = real(y);


Exp.Sequence = '3pESEEM';
Exp.Field = pars.B0VL*1000;
Exp.mwFreq = pars.MWFQ/(10^9);
Exp.dt = 0.008;
Exp.tau = 0.438;
Exp.T = 0.4;
Exp.nPoints = pars.XSpecRes;
Exp.ExciteWidth = 200;
Opt.ProductRule = 1;

A1iso=0.0041;
A1dip=0.2;
Sys1.Nucs = '1H';
Sys1.n = 5;
Sys1.S =1/2;
Sys1.A_=[A1iso A1dip];

Opt.Method='hybrid';
Vary1.A_=[0.003 0.3];
esfit('saffron',spec,Sys1,Vary1,Exp,Opt)

[Stefan Stoll]

We cannot check this script, since it loads experimental parameters from a file which you didn't attach.

Can you please post a script that demonstrates this without loading experimental data?

[Khalil]

Many Thanks Stefan,
I have attached a simple script of 3pESEEM of 1H nuclei. For multiple nuclei it seems that the modulation depth is not showing any changes with the number of nuclei regardless if you use "Sys.n" or setting multipe nuclei '1H,1H,..'. But in the frequency domain the amplitude of the signal did change with the number fo the nuclei only when I set the nuber of the nuclei as '1H,1H,.....' and not as Sys.n. Maybe my script is wrong but any thoughts are much appreciated.
Many thanks again.

[Stefan Stoll]

Sys.n is not used by saffron - we will add an appropriate error message.

If I run the following script, I do see the expected differences in modulation depth between 1 and 2 equivalent nuclei. The modulations won't visually change, since both protons have the same hyperfine coupling and modulate only weakly. Therefore, fundamental modulation frequencies are identical, and inter-nuclear combination peaks are very weak.

Code: Select all

clear, clf, clc

Exp.Sequence = '3pESEEM';
Exp.Field = 352.3;
Exp.dt = 0.010;
Exp.tau = 0.1;
Exp.T = 0.06;
Opt.ProductRule = 1;

A1 = [2 -1];

Sys1.Nucs = '1H';
Sys1.A = A1;

Sys2.Nucs = '1H,1H';
Sys2.A = [A1; A1];

[x1,y1,z1] = saffron(Sys1,Exp,Opt);
[x2,y2,z2] = saffron(Sys2,Exp,Opt);

plot(x1,y1/(4*pi),x2,y2/(4*pi))