Separating Nuclear Manifolds

[AKittell]

Is there a way to visualize the contributions of each nuclear quantum number separately? We are interested in seeing how the mi = +/- 1 manifolds change as a function of rotational correlation time, but want to avoid the effects of overlap.

[Matt Krzyaniak]

You can use the output option 'separate' to return the individual transitions contributing to the spectrum.

Add the following bit to your simulation code

Code: Select all

Opt.Output = 'separate'; 
chili(Sys, Exp, Opt)

[AKittell]

Thanks Matt. That's precisely what I was looking for.

For those interested, you can export the simulation into a three column matrix and isolate each column.

Thanks again.

[AKittell]

After playing around with 'separate' and 'summed' for a while, I've noted that when you include any line broadening, the 'separate' option tends to get a little messed up. I'm currently running simulations with a 0.2 mT line broadening, and that results in identical manifold shapes with different intensities. Remove the broadening, and the manifolds separate correctly. Parameters are below. Let me know if you have the same issue. (EasySpin v 5.0 Beta)

Sys =
g: [2.0088 2.0061 2.0023]
A: [17.3600 12.0400 100.5200]
Nucs: '14N'
tcorr: 1.0000e-08
lw: [0 0] OR lw = [0.2 0]

Exp =
CenterSweep: [338.7000 15]
mwFreq: 9.5000

Opt =
Output: 'separate'

[AKittell]

In principle, shouldn't the separate manifolds add up to the summed simulation with a three times the intensity? I have found this not to be the case using chili.

[Stefan Stoll]

Can you please post your simulation script? Use the "Code" button when composing the reply.

[AKittell]

Here's the code for summing the separated manifolds:

Code: Select all

Sys.g = [2.0088,2.0061,2.0023];
Sys.A = [6.2*2.8, 4.3*2.8, 35.9*2.8];
Sys.tcorr = 1e-8;
Sys.lw = [0 0];
Sys.Nucs = '14N';

Exp.CenterSweep = [338.7 15];
Exp.mwFreq = 9.5;
Exp.Harmonic = 0;
Exp.nPoints = 4096;

Opt.Output = 'separate';
Opt2.Output = 'summed';

Separated = chili(Sys,Exp,Opt);
Summed = chili(Sys,Exp,Opt2);
Sep0 = Separated(2,1:4096);
Sep_1 = Separated(1,1:4096);
Sep1 = Separated(3,1:4096);
SepSum = (Sep0+Sep_1+Sep1)/3;

plot(SepSum)
hold on
plot(Sep_1/3,'k')
plot(Sep1/3,'k')
plot(Sep0/3,'k')
plot(Summed,'r')

And then watching the manifolds completely change when line broadening is included:

Code: Select all

Sys.g = [2.0088,2.0061,2.0023];
Sys.A = [6.2*2.8, 4.3*2.8, 35.9*2.8];
Sys.tcorr = 1e-8;
Sys.lw = [0 0];
Sys.Nucs = '14N';

Exp.CenterSweep = [338.7 15];
Exp.mwFreq = 9.5;
Exp.Harmonic = 0;
Exp.nPoints = 4096;

Opt.Output = 'separate';

chili(Sys,Exp,Opt)
figure
Sys.lw = [0.05 0];
chili(Sys,Exp,Opt)

[Stefan Stoll]

Hi Aaron, thanks for spotting this. This is a bug. Separating transitions does not generally work when using the Stochastic Liouville equation.

Please do not use Opt.Output='separate' with chili. It continues to work correctly for the other simulation functions.