Abstract
A summary is given of molecular constants for NH3 and ND3, 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 re = 1.0116 × 10−8 cm., he = 0.381 × 10−8 cm.