EasySpin forum

If the coupling between the triplet and the nitroxide is small, then it should still be possible to use Exp.Temperature . You'll need to give populations for all 6 electron manifolds. Something along this should work: clear Sys.S = [1 1/2]; Sys.Nucs = '14N'; Sys.A = [0 0 0, 20 20 80]; Sys.D = [1000 ...

User-specificed populations in Exp.Temperature have primarily been designed for photoexcited spin-polarized S=1 states: The populations at field are calculated from the populations of the zero-field states , which are given in Exp.Temperature. Here's how the population calculation works currently (a...

I think I have located the origin of this behavior. Both the LM and the simplex algorithm depend on simulating spectra with slightly different parameters to determine local derivatives in the parameter space (Jacobian for LM, a small simplex for the simplex algorithm). The local derivatives then gui...

In 4.5.5, the simplest way of getting the rmsd after running esfit is [bestSys,bestSpec] = esfit('pepper',expSpec,...) residuals = expSpec - bestSpec; rmsd = sqrt(mean(residuals.^2)) This rmsd is directly based on your experimental data and the best fit, whereas the rmsd displayed by the esfit UI an...

Sys.ee includes all forms of electron-electron interactions, no matter what the physical origin is.
Check out the corresponding ES documentation.

Did you mean [-1 -1 2]*270? If yes, this is just the through-space dipolar coupling between two electron spins,
aligned along the z axis.

That's an inaccuracy in the documentation. The termination tolerance for Levenberg/Marquardt is FitOpt.TolStep, but for the simplex it is FitOpt.TolEdgeLength: When the edge length of the N+1-dimensional simplex falls below that number, the algorithm will terminate.

I'll fix the documentation.

Putting some degree of parallelization into ES has been on the to-do list for quite a while. The downside would be that it will require an additional toolbox. I am trying to keep ES running with the (admittedly somewhat feature-anemic) Matlab core.

You are trying to fit N=9 parameters simultaneously. In the simplex algorithm, esfit first computes N+1=10 spectra with slightly different parameter sets within your range to set up what's called the initial simplex. During these setup simulations, esfit does not check FitOpt.maxTime. Only after tha...