25 - The Low-Energy Electron-Induced Radiolysis of Carbon Dioxide:
Implications for Cosmic Ice Chemistry
The interaction of high-energy (up to 1020 eV) radiation (e.g., ? rays, cosmic rays) with condensed matter produces copious amounts of low-energy (< 20 eV) secondary electrons, which are thought to be to be the primary driving force in a wide variety of radiation-induced chemical reactions. One unique mechanism associated with these electron-induced reactions involves the formation of an intermediate called a transient negative ion which can subsequently dissociate to form a neutral radical and a negative ion. The goal of my experiments is to study the products and associated mechanisms of condensed phase carbon dioxide radiolysis induced by low-energy electrons at temperatures of ~ 90 K and pressures of ~10?9 Torr. A major objective of my research involves understanding the astrochemical processes that occur in the interstellar medium. Out there, solid dust grains covered with carbon dioxide-containing ices are subject to high-energy cosmic radiation. Understanding the low-energy electron-induced radiolysis of CO2 may explain the high-energy radiation-induced synthesis of €complex€ molecules (e.g., HCOOH) detected in the interstellar medium.