Vibration–rotation Bands of Ammonia: Ii. The Molecular Dimensions and Harmonic Frequencies of Ammonia and Deuterated Ammonia

A summary is given of molecular constants for NH 3 and ND 3 , as derived from high-resolution infrared spectra of a number of fundamental, overtone, and combination bands. Preliminary estimates are given for the equilibrium moments of inertia, the molecular dimensions, and the force constants of the harmonic potential function. The average molecular dimensions in the equilibrium configuration are r e = 1.011 6 × 10 −8 cm., h e = 0.381 × 10 −8 cm.