Volume 212, 2018

Spectral signatures of proton delocalization in H+(H2O)n=1−4 ions

Abstract

Couplings involving large amplitude vibrations in H+(H2O)n (n = 1–4) are explored using several theoretical approaches. These include harmonic treatments, analysis of harmonically coupled anharmonic oscillator (HCAO) models of the OH stretching vibrations, vibrational perturbation theory (VPT2) in internal coordinates, and diffusion Monte Carlo (DMC). It is found that couplings between shared proton stretches and HOH bends can lead to normal modes that are significantly mixed in character. Couplings between the various OH stretching vibrations are much weaker, and the OH stretches are well-described by harmonically coupled anharmonic oscillator models. Anharmonic couplings and the role of these large amplitude vibrations are further explored using DMC and VPT2. Based on the results of these calculations, it is found that all of the H+(H2O)n ions considered in this study display several different types of large amplitude vibrational motions even in their ground states. In the case of H7O3+, degenerate VPT2 calculations indicate that there are large couplings between the shared proton stretch and various lower frequency vibrations that correspond to motions that break the ionic hydrogen bonds. This leads to vibrational eigenstates that have contributions from several zero-order states.

Graphical abstract: Spectral signatures of proton delocalization in H+(H2O)n=1−4 ions

Associated articles

Supplementary files

Article information

Article type
Paper
Submitted
12 jún. 2018
Accepted
20 jún. 2018
First published
20 jún. 2018

Faraday Discuss., 2018,212, 443-466

Author version available

Spectral signatures of proton delocalization in H+(H2O)n=1−4 ions

L. C. Dzugan, R. J. DiRisio, L. R. Madison and A. B. McCoy, Faraday Discuss., 2018, 212, 443 DOI: 10.1039/C8FD00120K

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements