THE INVERSION POTENTIAL FOR NH3 USING A DFT APPROACH

Using a density functional theory approach, we generate a potential en ergy surface (PES) and, by a least-squares method, we obtain a polynom ial function which represents the unidimensional potential along the i nversion coordinate, with a very high precision. The inversion spectru m of NH3 is then determined by solving the Schrodinger equation for th is potential, using a better approximated reduced mass which is a func tion of the inversion coordinate. The calculated inversion frequencies obtained through this method are compared against those generated by Hartree-Fock theory and also with the experimental values. We find tha t our theoretical results are by far the most accurate. (C) 1998 Elsev ier Science B.V. All rights reserved.