LINEAR-RESPONSE CALCULATIONS OF ELECTRONIC G-FACTORS AND SPIN-ROTATIONAL COUPLING-CONSTANTS FOR DIATOMIC-MOLECULES WITH A TRIPLET GROUND-STATE

Electronic g-factors for ESR spectra of a number of diatomic molecules with a ground X(3)Sigma(-) State and their electronic spin-rotational coupling constants have been calculated by a linear response method. General expressions are used for the second order correction to the el ectronic g-factor which account for spin-orbit coupling induced admixt ures from all excited triplet states to the ground state orbital magne tism. First order corrections - the spin-Zeeman kinetic energy contrib ution and the one-electron spin-Zeeman gauge contribution - to the g-f actor are also accounted for. Calculated g-factors and spin-rotational coupling constants are in a good agreement with available experimenta l data. In particular, the positive, anomalous, sign of the spin-rotat ional coupling constant of the PF radical is reproduced. (C) 1998 Else vier Science B.V. All rights reserved.