Calculations of hyperfine coupling constant of the TMPD molecule

The calculations of the hyperfine coupling constants (HFCC) of tetramethyl-p-Phenylenediamine (TMPD) are presented. Several DFT functionals are employed and the results are compared with the UHF and MP2 level of theory. Sensitivity of HFCC to the choice of the basis set is investigated. Impact of the different conformers of TMPD and the equivalence of methyl group hydrogens on the HFCC values is considered. The solvent effects are introduced via polarizable continuum model and compared with in vacuo calculations. Last but not least, molecular dynamics is employed to include the solvent molecules as well as the dynamics explicitly, accounting similar conditions comparing to the liquid phase EPR experiment.