Perpendicular Vibrations of the Ammonia Molecule

Abstract

The vibration frequency ${\nu }_2$ of N${\mathrm{H}}_3$ is identified by means of the combination bands ${\nu }_2\pm {\nu }_3$ at 2.2μ and 4.0μ, in each of which the spacing between component bands is about 16 ${\mathrm{cm}}^{-1\mathrm{}}$. From the difference band the numerical value of ${\nu }_2$ is fixed at 3415 ${\mathrm{cm}}^{-1\mathrm{}}$. The fundamental band may be recognized in the weak and complex background of the absorption at 3μ. The coefficient ${\zeta }_2$ of the vibrational angular momentum is approximately +0.6.