SOLVENT EFFECTS ON NUCLEAR SHIELDINGS AND SPIN-SPIN COUPLINGS OF HYDROGEN SELENIDE

Solvent effects on the nuclear shielding and indirect spin-spin coupli ng constants of H2Se have been calculated by modeling the surroundings as a continuous dielectric medium. Gauge-origin independence of the n uclear shieldings is ensured by using London atomic orbitals in combin ation with linear response theory. We present the Linear response func tion of a solvated molecule subject to triplet perturbations and use a new implementation of this theory to evaluate the Fermi-contact and s pin-dipole contributions to the indirect spin-spin coupling constants, We present high-level calculations of the nuclear shielding and indir ect spin-spin coupling constants of H2Se in vacuum and different solve nts. Our results represent the first ab initio calculations of the spi n-spin coupling constants in H2Se as well as the first investigation o f medium effects on these properties. It is demonstrated that the solv ent shifts of the spin-spin couplings are caused by a polarization of the molecular electronic structure as well as by changes in the geomet ry upon solvation. (C) 1998 American Institute of Physics.