Propylbenzene-(H2O)n clusters: Effect of the alkyl chain on the π h-bond

Mishra, Piyush

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https://hdl.handle.net/2142/100810 Copy

Description

Title

Propylbenzene-(H2O)n clusters: Effect of the alkyl chain on the π h-bond

Author(s)

Mishra, Piyush

Contributor(s)

• Zwier, Timothy S.
• Sibert, Edwin
• Fischer, Joshua L.

Issue Date

2018-06-19

Keyword(s)

Clusters/Complexes

Abstract

This talk focuses on the mass resolved- resonant 2-photon ionization (R2PI), resonant ion-dip infrared spectroscopy (RIDIR) and IR-UV holeburning (IR-UV HB) spectroscopy of propylbenzene(pBz)-(H2O)n clusters and the comparison with their Benzene(Bz)-(H2O)n cluster counterparts, which are a well-studied prototype system for the π H-bond. Since the pBz monomer exists in gauche and trans conformers, one anticipates the presence of pBz-H2O complexes with H2O on the same or opposite sides of the ring as the gauche or trans propyl chain. Indeed, local minima associated with these four complexes were identified by dispersion-corrected DFT calculations. R2PI and IR-UV HB spectra of pBz-H2O show long Franck-Condon progressions associated with the set of conformers of the complex. The OH stretch RIDIR spectra consist of a single transition in the symmetric stretch region, and a doublet with varying spacing in the antisymmetric stretch region, indicating coupling to a large-amplitude motion (LAM). The changes in the OH stretch region indicate that the water molecule bound to propylbenzene undergoes more restricted motion on the π cloud than its Bz-H2O counterpart. The potential energy surface for H2O tumbling on the pBz π cloud was mapped out, and used as the basis for calculating from first principles the OH stretch infrared spectrum. Comparison with the spectrum for Bz-H2O further illustrates the source and restrictions of the LAM of H2O in pBz compared to Bz. OH stretch IR spectra of the higher water clusters pBz-(H2O)n with n=3, 4 are very similar to their Bz-(H2O)n counterparts, existing as H-bonded cycles, with no evidence of LAM on the aromatic π cloud.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100810

DOI

10.15278/isms.2018.TE09

Copyright and License Information

Copyright 2018 Piyush Mishra

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