A THEORETICAL INVESTIGATION OF THE EQUILIBRIUM ELECTRIC-DIPOLE MOMENTOF AMMONIA

From a series of highly accurate ab initio calculations, the non-relat ivistic CCSD(T) basis set limit value of the equilibrium electric dipo le moment (mu(c)) of NH3 has been determined. Further, the small effec ts of relativity and correlation beyond the CCSD(T) level on mu(c) hav e been estimated. The ab initio results strongly suggest that the rece nt experimental value of 1.561 D for mu(c) is too high and that the tr ue value is closer to 1.533 D. A possible resolution of this discrepan cy in terms of the experimental observations is proposed. (C) 1998 Els evier Science B.V.