Flash Photolysis of Methane in the Vacuum Ultraviolet. I. End-Product Analysis

Abstract

Methane and mixtures of methane and methane‐d₄ have been subjected to flash photolysis in the vacuum ultraviolet. Ethylene is the major hydrocarbon product. Isotopic distributions of the hydrogen, ethane, and ethylene fractions as well as complete product analysis suggest that CH plays a dominant role in the photolysis. The CH is formed either by direct dissociation of excited methane or secondary flash photolysis of CH₂ in the flash. On the basis that acetylene is formed with unit efficiency by association of CH and ethylene is formed by reaction of CH with methane, the collision yield of the latter reaction is about 1/80.