EasySpin forum

Hi, I am trying to fit an EPR profile with two interacting spins (1 and 1/2), defined as Sys1 and Sys2 respectively, with command "esfit('pepper', spc, {Sys1, Sys2}, {Vary1, Vary2}, Exp)". How to include J or ee parameters for the interaction between them? Thanks PS: Because of some reason...

Thanks Stefan for number of suggestions. To be honest, I was more interested in g, D, E & J values and did not give much importance to D&H strains. What you pointed out about D&H strain values makes sense, now, attached picture is the best I achieved so far without HStrain, though DStrai...

Here is the script, attached is the experimental data. Sys1.S = [1 1]; Sys1.g = [3.4 3.2 5.15; 3.67 3.92 2.82]; Sys1.HStrain = [13540 9.73E-12 926]; Sys1.DStrain = [1.7E-08 86; 1.14E-09 7.4E-06]; Sys1.D = [7714 -852; -2230 427]; Sys1.J = 1700; Exp.mwFreq = 9.538; Exp.Range = [0 250]; Exp.Harmonic = ...

Thanks Stefan, for the suggestion. I tried reversing the sign for one D&E set, and simulated spectrum is quite different. In fact the data I am trying to fit is collected at 5K...so it makes sense, as you said sign of D only relevant at low T. Does this mean that the opposite signs of D are rela...

I am trying to fit two exchange coupled triplets. I am getting opposite signs of D & E parameters for them (D > 0, E < 0 and D < 0, E > 0) with similar magnitudes. Which of two inference should I make - 1. I have chosen different frames of reference for them while giving preliminary D&E valu...

Dear joscha_nehrkorn, I am also following the same idea of not defining Euler's angles so frame of reference for two ions in a molecule be same. The only concern I have is in that case my D & E values should be similar. Though I am getting +ve D, -ve E for first ion and -ve D, +ve E for second w...

Dear thanasis, Our concerns converge now. I am also trying to figure out something similar for two exchange coupled ions. If I only define Sys.g etc. in ES without referring to any preferred frame of reference, would the reference frameschosen by ES by default for two ions be same (all axes parallel...

Hi, I have a follow up question regarding the Frame of reference in a molecule with two S = 1 spins/unit cell. I am using the default frame of reference of EasySpin, and was expecting similar D & E values initially. But, pepper fitting is giving similar D & E magnitudes with their signs oppo...

Does it mean that J, eeD and dvec model (all together) will not work for two spins which are not identical (having dissimilar g tensors)? If so and then if I use Sys.ee, J_anisotropic would be Sigma Jij/3 but how can I calculate Jdip from Sys.ee 3X3 tensor ?

Actually I am considering non-identical g tensors for two centers due to the different crystal fields at them which may arise due to crystallographically non-identical positions. This non-identical positions may be anything depending upon the crystallographic details. Now, this brings up my question...