Parallel/Perpendicular Mode

[ram439]

This simulation closely resembles our experimental results:

Exp.Mode = 'perpendicular';
Exp.mwFreq = 9.4;
Exp.Range = [270 400];
Sys = struct('S',5/2,'g',2,'Nucs','55Mn','A',253,'lw',1);
Sys.D = 170;
Sys.DStrain = 120;
[B,spec] = pepper(Sys,Exp);
plot(B,spec);

However...

If we change to Exp.Mode = 'parallel';

The resonance shows 5 lines for manganese instead of 6, and we can't reason why this would happen by switching modes.

Experimentally, we have a dual mode cavity and see 6 lines regardless of mode.

Thanks!

[Stefan Stoll]

The prominent peaks in the simulated parallel-mode spectrum are the five central -1/2 -> +1/2 (delta-mS = +1) transitions with delta-mI = -1, so that delta-mS + delta_mI = 0. These transitions are forbidden and very weak in perpendicular mode and are also very weak in parallel mode.

If you compare the overall intensities of the perpendicular vs parallel mode, you will see that the parallel-mode spectrum is several orders of magnitude weaker than the perpendicular-mode spectrum.

Experimentally, you might be seeing some admixture of the (strong) perpendicular-mode spectrum to the (very weak) parallel-mode data.

[Stefan Stoll]

Here is a script that illustrates this:

Code: Select all

clear, clc, clf

Sys.S = 5/2;
Sys.g = 2;
Sys.D = 170;
Sys.Nucs = '55Mn';
Sys.A = 253;
Sys.lw = 0.5;

Exp.mwFreq = 9.4;
Exp.Range = [270 400];
Exp.Harmonic = 0;

% Full spectra
Exp.Mode = 'perpendicular';
[B,spec_perp] = pepper(Sys,Exp);
Exp.Mode = 'parallel';
[B,spec_para] = pepper(Sys,Exp);

% Only -1/2 -> +1/2 transitions with delta_mI = -1
Opt.Transitions = [13 23; 14 22; 15 21; 16 20; 17 19];
Exp.Mode = 'perpendicular';
[B,spec5_perp] = pepper(Sys,Exp,Opt);
Exp.Mode = 'parallel';
[B,spec5_para] = pepper(Sys,Exp,Opt);

% Plotting
subplot(2,1,1)
plot(B,spec_perp,B,spec5_perp);
legend('perp all','perp -1/2->+1/2, dmI=-1');
legend boxoff
title('Perpendicular mode')
axis tight
subplot(2,1,2)
plot(B,spec_para,B,spec5_para);
legend('para all','para -1/2->+1/2, dmI=-1');
legend boxoff
title('Parallel mode')
axis tight