Experimental and computer studies of the kinetics and distribution of vibrational energy in both products of the reaction: O(3 P)+ CS2? SO + CS

Abstract

The reaction, O(3P)+CS2→SO + CS (2), was initiated by flashing NO2+CS2 mixtures with radiation of wavelengths >3000 A. Its progress was monitored by kinetic absorption spectroscopy of the CS A1Π–X1∑+(0,0) band and these measurements yielded log10k2= 9.8(±0.2)–600(±300) cal/mole/2.303RT.At higher NO2 and CS2 concentrations, other absorption bands, from both this system and the SO B3∑––X3∑– system, were observed. By comparing the relative intensities of bands from different ground state vibrational levels, the relative rates into individual quantum states were determined and the total vibrational energy yields were estimated to be 8 % of –ΔH in CS and about 18 % in SO. A preliminary investigation of the kinematics by computer simulation of collinear reactions over various energy hypersurfaces showed that excitation of the CS vibration results from release of energy as repulsion between the products. The yield is sharply dependent on the steepness of the interaction potential between the separating products and seems likely to vary with the impact parameters of the reactive collision.