Simulating Average Dipolar Coupling in Solution State

[AdamS]

Is there a way to simulate the average dipolar couplings between mono-radicals in solution state?

For example, I would like to simulate the average dipolar couplings between 4-Hydroxy TEMPO mono-radicals in solution at room temperature for increasing concentrations (1.5 to 12 mM) of 4-Hydroxy TEMPO. From what I can find only "pepper" has the ability to use "ee", however, that is for the solid-state.

Thanks in advance for any help.

[Stefan Stoll]

I am not sure what you need. In solution, dipolar couplings average out to zero.

[AdamS]

Correct, dipolar couplings are averaged out in solution. I guess the more accurate question is, how should I simulate the broadening observed in the spectra below? When I simulate with either "garlic" or "chili' the fit is very close, however, it does not seem to fit the broadening very well. I allow the parameter lwpp to be varied as well as the g, A, and logtcorr parameters.

The spectra were collected at room temperature and are area normalized to 1. I was told that the observed broadening was "dipolar broadening".

Spectra

TEMPOL.png (144.98 KiB) Viewed 3642 times

Thanks again for any help.

[Stefan Stoll]

I think you mean concentration-dependent broadening due to electron-spin exchange. To account for that in the simulations, use convolutional Lorentzian broadening with Sys.lwpp = [0 lw]; and vary lw with concentration.