DENSITY-FUNCTIONAL CALCULATIONS OF ISOTROPIC HYPERFINE COUPLING-CONSTANTS OF RADICAL CATIONS

The hyperfine (hf) structures of radical cations are calculated using first principles density functional theory. Within the local spin dens ity (LSD) approximation, the isotropic hyperfine coupling constants (F ermi contact terms) are computed for a set of linear (nonbranched) alk ane and alkene radical cations with up to four carbon atoms. The resul ts are as a whole in very good agreement with experimental data, obtai ned from low temperature matrix isolation electron-spin resonance (ESR ) measurements, and with results from previous configuration interacti on calculations.