Theory of the profiles of hydrogen stretching infrared bands of hydrogen-bonded solids - Fermi resonance effect and strong coupling between the high-frequency hydrogen stretching vibration and low-frequency phonons

A theory is developed to describe the profiles of hydrogen stretching infra red bands of hydrogen-bonded solids taking into account the anharmonic coup ling between the high-frequency stretching vibration, nu(XH), and low-frequ ency lattice phonons as well as a Fermi resonance between states involving the nu(XH) stretching and an overtone or combination of some internal modes . The theory was constructed in the framework of the extended molecular exc iton Davydov approach. (C) 1999 Elsevier Science B.V. All rights reserved.