Photochemistry of Cyclopentanone. II. Transfer of Vibrational Energy from the Excited State

Abstract

The photochemical production of carbon monoxide, ethylene, cyclobutane and 4-pentenal from cyclopentanone at constant temperature, pressure and wave length (3130 Å.) have been studied as a function of the pressure of inert gases. Argon, hydrogen, methane, carbon dioxide, cyclopropane and cyclobutane have been used as inert gases. In all cases, over the pressure ranges used (10 to 400 mm.), the amount of ketone photolyzed, as determined by mass balance, was independent of the total pressure. The results have been interpreted to mean that the vibrational energy of the ketone molecule is lost gradually (one or a few quanta at a time). From a quantitative interpretation of the data, relative efficiencies for the inert gases for the transfer of vibrational energy from cyclopentanone have been obtained. © 1961, American Chemical Society. All rights reserved.