Heterogeneous Deactivation of Excited Molecules
Several researchers developed the methods for studying the heterogeneous deactivation of vibrationally excited molecules and obtained the values of accommodation coefficients for different surfaces. This chapter reviews the results of work carried out mainly at the Institute of Chemical Physics. It discusses the deactivation of nitrogen on silver, and deuterium and nitrogen on copper and tungsten. These materials have been chosen for the following reasons: silver and copper do not chemisorb nitrogen, but tungsten adsorbs nitrogen dissociatively. Copper does not adsorb deuterium, but tungsten adsorbs deuterium dissociatively. The chapter considers the excitation of electron-hole pairs as a possible microscopic mechanism for deactivation of a diatomic vibrationally excited molecule near the metal surface. The deactivation of singlet oxygen in the gas phase along with the exchange processes with molecules capable of light irradiation has been much studied. The main problem in investigations of heterogeneous deactivation of singlet oxygen is connected with the measurement of its concentration.