Identification of the C̃ State of Ammonia by Electron Impact Spectroscopy

Abstract

The relative intensities of the $\mathrm{B̃\hspace{0.17em}\leftarrow \hspace{0.17em}X̃}$ and $\mathrm{C̃\hspace{0.17em}\leftarrow \hspace{0.17em}X̃}$ transitions in ammonia have been measured by electron impact spectroscopy. Spectra were obtained for electrons of 90‐ and 250‐eV incident energies with scattering angles of 0° to 3°. Analysis of the relative intensities, in conjunction with the ultraviolet data previously reported by Douglas, indicates that the $\mathrm{C̃}$ state is a separate excited electronic state of ammonia, identified by the term symbol ${}^1{A}_1\prime$ .