EasySpin forum

Hello

I would like to fit isotropic exchange in trinuclear system, defined as

Sys.S = [3/2 3/2 3/2];
Sys.J = [J12 J13 J23];

and the question is whether it is possible to restrict J13=J23 relationship in ESFIT?
If yes, I would have only two varying parameters, J12 and J13 (J23=J13)...

Thank you for your kind reply

To achieve this, write your own simulation function, see the user guide on fitting.

Use your own custom Sys fields for the exchange couplings, e.g. Sys.J12 and Sys.J13, and then in the simulation function, set Sys.J = [Sys.J12 Sys.J13 Sys.J13] and call pepper. You can then vary Sys.J12 and Sys.J13 with esfit.