Chemiluminescent matrix reactions of atomic oxygen, sulfur, and O(3P)+H2S

Abstract

Optical multichannel techniques have been used to analyzed the visible chemiluminescence generated by diffusion‐controlled warmup (8→20 °K) of separate, uv‐photolyzed inert gas matrices containing O3, H2S, H2S+O2, and O3+H2S molecules. Oxygen atoms were observed to diffuse and recombine in solid argon at ∼17 °K to produce the intense Herzberg I band system of molecular O2 (A→X) which was also observed in krypton though not in xenon matrices. The lack of any detectable emission in xenon was attributed to premature diffusion and depletion of atomic oxygen prior to diffusion‐controlled warmup. Matrix diffusion and recombination of sulfur atoms produced intense S2 emission (B→X) in all three matrices (Ar, Kr, Xe). Long, structured vibrational progressions (0,ν″) were observed in argon and krypton, while a broad, relatively structureless emission was observed in xenon. Suggested mechanisms for this latter effect include such processes as vibrationally unrelaxed fluorescence and/or S2*–Xe van der Waals ’’complex’’ formation. Diffusion of sulfur atoms in matrices containing traces of molecular O2 produced the phosphorescent emissions of SO2 (a→X) which appeared to be orders of magnitude more intense than the S2 emissions. Oxygen atoms were observed to diffuse and react with H2S molecules in dilute argon matrices at ∼14 °K, thereby generating SO2phosphorescence (a→X) as well as two emission systems of lesser intensity (520–675 nm), each with an approximate vibrational spacing of ∼1040 cm−1. Suggested emitter(s) responsible for these latter chemiluminescent systems are presented.