Dynamics of Vibrationally Excited Polyatomic Molecules and Their Unstable Isomers on the Electronic Ground State Potential Surface. Progress Report

摘要

The general goal of this research is to understand the role of vibrational energy in chemical reactions related to energy production. Since the start of this grant in August 1986, we have made several advancements, both in the development of methodology and in science, toward understanding the chemical properties of highly vibrationally excited molecules. A transient vibrational spectroscopic method -- Flash Photolysis Stimulated Emission Pumping -- for radical species has been developed. The vibration-rotation levels of a radical, generated by flash photolysis at a concentration approximately greater than 10(sup-4) Torr, and with a lifetime of approximately greater than 10(sup-8) sec, can be characterized with 0.04 cm(sup-1)/ resolution over a wide energy range (up to 10(sup 4)/cm). This method was first demonstrated on CH2. Using Stark Level-Crossing Spectroscopy, we have shown that highly excited, single vibration-rotation quantum states of small polyatomics can be characterized with great detail. This can be done even though these levels are dissociative, have high densities, and are optically inaccessible. 17 refs., 2 figs., 4 tabs.