The nuclear spin-spin coupling constants in the water dimer

The nuclear spin-spin coupling constants have been calculated for the water dimer, as well as for the water monomer and dimer surrounded by the dielec tric medium. The change due to condensation has been estimated at similar t o 12 Hz for \J(O-H)\ and similar to 0.4 Hz for \J(H-H)\. The performance of different basis sets: and electron correlation effects, as estimated by th e MCSCF wavefunctions, have been investigated. The latter are particularly important for J(H-H). The calculated changes in both J(O-H) and J(H-H) coup ling constants an dominated by the Fermi contact and paramagnetic spin-orbi tal terms. (C) 1999 Elsevier Science B.V. All rights reserved.