The NH and ND stretching fundamentals of 14ND2H

High resolution (0.004 cm(-1) instrumental bandwidth) interferometric Fourier transform infrared spectra of (ND2H)-N-14 were obtained on a BOMEM DA002 spectrometer under essentially Doppler limited conditions. We report the analysis of the ND and NH stretching fundamentals of (ND2H)-N-14 with term values for the symmetric (s) and antisymmetric (a) sublevels with respect to the inversion plane of the planar geometry T-v (s)=2430.7990(7) cm(-1) and T-v (a)=2434.6222(8) cm(-1) for the nu(3a) fundamental, T-v (s)=2559.8069(8) cm(-1) and T-v (a)=2559.9630(9) cm(-1) for the nu(3b) fundamental and T-v (s)=3404.238(5) cm(-1) and T-v (a)=3404.316(5) cm(-1) for the nu(1) fundamental. The two modes nu(3) which are degenerate in ND3 and whose degeneracy is lifted in ND2H, are distinguished by the subscripts 3a or 3b, being symmetric (3a) or antisymmetric (3b) with respect to the C-s plane of symmetry of the equilibrium geometry of ND2H. Up to 20 molecular parameters of the effective S-reduced Hamiltonian could be determined accurately for each fundamental. In particular, the inversion-rotation interaction parameter could be determined for the two ND-stretching modes. Assignments were established with certainty by means of ground state combination differences. The results are important for the mode selective inhibition or catalysis of inversion at the nitrogen atom by exciting ND and NH stretching vibrations, for treatments of isotope effects on inversion of ammonia by means of effective Hamiltonians as well as true molecular Hamiltonians on high dimensional potential hypersurfaces. (C) 2003 American Institute of Physics.