THE IMPORTANCE OF QUARTIC ANHARMONIC RESONANCES IN OVERTONE SPECTROSCOPY

Abstract

Anharmonic resonances play a key role in our understanding of high overtone spectroscopy. The resonance polyads to which they give rise grow in dimension, and the magnitude of the coupling terms grow, as we ascend the energy scale and the corresponding density of states, until eventually all pattern in the spectrum of vibrational states is lost. The most familiar resonances are Fermi resonances, involving cubic anharmonic couplings. In this talk I shall show a number of examples where quartic anharmonic couplings play a role that is perhaps more important than the familiar cubic Fermi resonances, despite the fact that they are often neglected in vibrational analysis.