Fluorescence of nitric oxide. Part 6.—Predissociation and cascade quenching in NO D2Σ+(v= 0) and NO C2Π(v= 0), and the oscillator strengths of the ε(0,0) and δ(0,0) bands

Abstract

Argon induces the transition NO D²Σ⁺(v= 0)→NO C²Π(v= 0) with unit efficiency. Nitrogen, carbon dioxide and nitric oxide do not induce the cascade transition. The rate of spontaneous predissociation of NO D²Σ⁺(v= 0) is shown, by two methods, to be small compared to the rate of spontaneous emission. The characterization of the [graphic ommitted] process is complicated because the δ-bands simultaneously undergo a partial quenching which masks the enhancement due to the cascade transition. The two effects were separated by restricting the population of NO D²Σ⁺(v= 0) with filtered light. With high inert-gas pressures (rotational equilibrium) it was estimated that NO C²Π(v= 0) predissociates 33±5 times more rapidly than it radiates to the ground electronic state. The oscillator strengths of the ε(0,0) and δ(0,0) bands were measured by two methods. Whilst Bethke's ³f^ε₀₀= 25.4 × 10^–4 was confirmed, his ^δ₀₀ was shown to be too small by a factor of ∼2.3. The f^δ₀₀ was recorded as 56(±10)× 10^–4.