Classical dynamics of energy transfer between bonds in A B A triatomics

Abstract

A discussion of energy transfer betwen bonds is presented for ABA triatomics for which a local mode picture affords a good zeroth‐order description. A model of H₂O is used to illustrate the discussion. It is shown that the energy transfer between the bonds can be readily understood both qualitatively and quantitatively in terms of the dynamics of a twofold hindered rotor. The transformation to this representation leads to a simple picture of the transition from ’’local mode’’ to ’’normal mode’’ behavior and to simple analytic expressions for the energy transfer rates. These predicted rates are found to be in excellent agreement with trajectory calculations. Isotope effects are discussed for the H₂O–D₂O pair.