THEORETICAL-STUDY OF THE RENNER-TELLER (A)OVER-TILDE2A1-(X)OVER-TILDE2B1 SYSTEM OF NH2

Three-dimensional potential energy functions of the A B-2(1)-X 2A1 bent-bent Renner-Teller system of NH2 have been generated and used in calculations of the rovibronic energy levels (J less-than-or-equal-to 9/2) by a variational approach accounting for anharmonicity, rotation-vibration, electronic angular momenta and electron-spin coupling effects. For low values of N, the theoretical rovibronic term values up to about 20000 cm-1 agree with available experimental data to within a few wavenumbers. For the first time, all existing rovibronic states for N = 0 and 1 are given and assigned up to 18000 cm-1. For higher levels including stretching modes the Fermi polyads have been used in the assignments.