Effect of hydrogen bonding on the infrared absorption intensity of OH stretch vibrations

Athokpam, Bijyalaxmi and Ramesh, Sai G and McKenzie, Ross H (2017) Effect of hydrogen bonding on the infrared absorption intensity of OH stretch vibrations. In: CHEMICAL PHYSICS, 488 . pp. 43-54.

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Abstract

We consider how the infrared intensity of a hydrogen-bonded OH stretch varies from weak to strong H-bonds using a theoretical model. We obtain trends for the fundamental and overtone transition intensities as a function of the donor-acceptor distance, a common measure of H-bond strength. Building upon our earlier work using a two-diabatic state model, we introduce a Mecke function-based dipole moment for the H-bond and calculate transition moments using one-dimensional vibrational eigenstates along the H-atom transfer coordinate. The fundamental intensity is found to be over 20-fold enhanced for strong H-bonds, where non-Condon effects are significant. We analyse isotope effects, including the secondary geometric isotope effect. The first overtone intensity varies non-monotonically with H-bond strength; suppression occurs for weak bonds but strong enhancements are possible for strong H-bonds. We also study how these trends are affected by Mecke parameter variations. For a few specific dimers, we compare our results with earlier works. (C) 2017 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Publication:	CHEMICAL PHYSICS
Additional Information:	Copy right for this article belongs to the ELSEVIER SCIENCE BV, PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS
Department/Centre:	Division of Chemical Sciences > Inorganic & Physical Chemistry
Date Deposited:	25 May 2017 08:57
Last Modified:	25 May 2017 08:57
URI:	http://eprints.iisc.ac.in/id/eprint/57038

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