The C ̃¹B_u ← X ̃¹Σ_g⁺ Transition of Ethanedinitrile (C₂N₂): Assignment of the Electronic State Origin and Vibrational Bands

Abstract

An analysis is presented for the vacuum ultraviolet CN C̃B ← X̃Σ transition. Contrary to previous assumptions this is found to be a linear to bent transition with a trans-bent CB excited electronic state. The band origin is at 59 840 cm. Vibrational bands between 170 and 145 nm are assigned. Vibrational frequencies for the C̃B state are found to be ν = 2055 ± 20 cm for the symmetric CN stretch, ν = 979 ± 20 cm for the symmetric CC stretch, ν = 542 ± 10 cm for the trans-bend, ν = 131 ± 10 cm for the out-of-plane torsional bend, and ν = 141 ± 10 cm for the cis-bend.