Recombination Reactions of Atomic Chlorine in Compressed Gases. 1. Chemiluminescence Spectra of Chlorine Molecules with Argon Pressure Up to 170 bar

Abstract

The gas-phase chemiluminescence spectra of chlorine atom recombination reactions in argon with pressures up to 170 bar were recorded by the laser photolysis/chemiluminescence detection scheme. With the spectroscopic data available in the literature and the monochromator functions determined experimentally and by assuming that the pressure line broadenings and frequency shifts follow the conventional Lorentzian form, for the first time the chemiluminescence spectra were quantitatively decomposed into the emissions of the B 3 Π(0 u + ) f X 1 Σ g + and A 3 Π(1 u ) f X 1 Σ g + transitions. The relative luminescence weights of these two emission electronic states, the vibrational temperatures, the pressure line broadenings, and frequency shifts were obtained. Their implications on the mechanisms of the chlorine atom recombination reactions and the interaction strength between the chlorine molecule and argon atom were discussed.

Recombination Reactions of Atomic Chlorine in Compressed Gases. 3. Molecular Dynamics and Smoluchowski Equation Studies with Argon Pressure up to 6 kbar

“…The photodissociation/recombination reactions of the molecular halogens in compressed rare gases have received continual attention for more than two decades. − They are generally regarded as model reactions for the study of the photolytic cage effect in the bulk systems. Experimentally, for the earlier studies, the photolysis quantum yields and the nongeminate atomic recombination rate constants of iodine, bromine, and chlorine were measured and the mechanisms for geminate recombination were proposed. − Along this general line, the onset of the geminate recombination reactions of the chlorine molecules in the lower pressure region was investigated recently. , Meanwhile, in another different experimental development, the geminate recombinations of the I 2 /Xe system were intensively studied by the picosecond transient absorption method. , In the past few years, the real-time dynamics of the iodine dissociation/recombination reactions in the rare gas cages over a wide range of gas pressures have been investigated with femtosecond time resolution. − …”

Recombination Reactions and Diffusive Properties of Diatomic Molecules in Two Different Microporous Structures: Silicalite and ZK4

“…We also separately investigate the diffusive properties, in the same environments, of the atomic and molecular species involved in the reactions. In this report we will not attempt a direct comparison with the available experimental data on photodissociation−recombination reactions of halogens in condensed phases or in compressed rare gas cages. − This class of reactions is used here mainly as a probe to explore the diverse dynamical response of the two zeolites, without considering the exact reaction dynamics, whose simulation would not be feasible with the simple model adopted to make the calculations viable. Indeed, we do not consider the participation of excited electronic states in the dissociation−recombination process; the curve-crossing dynamics should be included in the simulations in order to achieve a more detailed description of the exact reactive dynamics, , but we preferred to model the recombination as occurring on a single electronic surface because this simplification allows longer simulation times, which are required to reach the main purpose of our study.…”