Photodissociation lifetime of 32S2 molecule in comets

Abstract

Photodissociation lifetime of 32s2in comets is calculated by absorption of solar photons into the B3Σ− state and velocity distributions of sulphur atoms are determined. Absorption of solar photons of wavelength ~ 280 nm leads to a photodissociation lifetime of about 250 s for 32S2 molecule in comets when sun-comet distance is 1 AU. Forbidden lines corresponding to 1D-3P transitions of neutral sulphur atom may be detectable at about 11 306 and 10 821 A in comets. The production rate of 32S2 dimer in comet IRAS-Araki-Alcock 1983d compares well with the production rate of CS, observed in comet Bradfield, when compared at the same heliocentric distance. The chemistry of 32S2 dimer formation in the inner coma of a comet is discussed in the framework of some gas phase reactions.