Light emission of the photofragments produced by photolysis of ammonia and ammonia- d3 at 147, 123.6 and 104.8 nm: : First observation of the b 1Σ + → X 3Σ − transition of NH and ND

Abstract

Excited photofragments are produced by vacuum ultra-violet photolysis of gaseous ammonia and ammonia- d 3. The following transitions have been recorded: NH 2(ND 2) Ã 2A 1 → X̃ 2B 1 by irradiation with xenon and krypton resonance lamps; NH (ND) c 1π → a 1Δ and b 1Σ + → X 3 Σ − with the krypton and argon resonance lamps. This last emission, observed here for the first time, occurs at 471 nm and it leads to the singlet—triplet splitting a 1Δ − X 3Σ − of NH, with an energy of 1.561 eV (1.565 eV for ND). The rotational temperatures of the c and b excited states of NH and ND radicals have been measured and the primary processes leading to the excited photofragments are discussed.