THEORETICAL FOUNDATIONS FOR A NEW FAMILY OF INFRARED 4-WAVE-MIXING SPECTROSCOPIES

A new family of selective four-wave mixing methods, based on the estab lishment of vibrational nonlinear polarizations with multiple resonanc es, is proposed. This family includes double-infrared resonances, vibr ationally enhanced Raman resonance, and vibrationally enhanced two-pho ton resonance. These methods are related to traditional Raman and infr ared spectroscopy, but the methods are shown to have the capabilities for component and conformer selectivity, line-narrowing of inhomogeneo usly broadened vibrational transitions, and mode selection. The theore tical foundations for the methods are developed and directed to possib le applications.