The Visible Absorption Spectrum of Matrix-Isolated NH<inf>2</inf> and Its Deuterides - Comparison with Calculated Spectroscopic Properties

Abstract

Absorption spectra of matrix-isolated NH2 and its deuterides were measured in the range 370- 880 nm. Comparison with calculated term values, transition moments, spin-orbit splittings, and with gas-phase data rendered possible the nearly complete assignment of the spectra. At 5 K the Ã2A1, X̃2B1 (v1, v2, 0) ← X̃2B1 (0, 0, 0) system consists of Π-bands, and of very weak Σ* ← Σ and Δ* ← Σ bands which are induced by a local translational mode of ca. 70 cm-1. At elevated temperatures regular Σ and Δ bands have also been identified. This fact as well as the temperature dependence of the band shapes confirms that the radicals undergo (nearly) free rotation in therare gas cage. Term values and intensity distributions are well reproduced by the calculations, ifallowance is made for intensity borrowing by assigned and some unassigned Fermi resonances. © 1993 Academic Press, Inc.