Quantum monte carlo simulation of vibrational frequency shifts in CO in solid para-hydrogen

Wang, Lecheng

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https://hdl.handle.net/2142/50789 Copy

Description

Title

Quantum monte carlo simulation of vibrational frequency shifts in CO in solid para-hydrogen

Author(s)

Wang, Lecheng

Contributor(s)

• Roy, Pierre-Nicholas
• Le Roy, Robert J.

Issue Date

2014-06-20

Keyword(s)

Clusters/Complexes

Abstract

Stimulated by Fajardo's remarkable study of the rovibrational spectra of CO isotopologues trapped in solid $para$-hydrogen,\footnote{\,M.\ E.\ Fajardo, {\em J.\ Phys.\ Chem.\ A}\ {\bf 117}, 13504 (2013).} we have performed quantum Monte Carlo simulations to predict his observed vibrational frequency shifts and inertial rotational constants using 2-body potentials based on the best available models for the {\it p}H$_2$-{\it p}H$_2$\,\footnote{R. Hinde, {\it J.\ Chem.\ Phys.}\ {\bf 128}, 154308 (2008).} and CO-{\it p}H$_2$\,\footnote{\,H.\ Li, X-L.\ Zhang, R.J.\ Le Roy, and P.-N.\ Roy, {\em J.\ Chem.\ Phys.}\ {\bf 139}, 164315 (2013).}~ potential energy functions. We started by fitting an analytic `Morse/Long-Range' (MLR) function\footnote{\,R.J.\ Le Roy, C.C.\ Haugen, J.\ Tao and Hui Li, {\it Mol.\ Phys.}\ {\bf 109}, 435 (2011).} to the 1D ``adiabaic hindered rotor'' version of Hinde's 5D {\it p}H$_2$-{\it p}H$_2$ potential developed by Faruk {\it et al.}\footnote{\,N.\ Faruk, R.J.\ Le Roy, and P.-N.\ Roy, {\em J.\ Chem.\ Phys.}\ (submitted December 2013).} We then modified it to take account of many-body effects by scaling it until it yielded the correct equilibrium lattice parameters for the {\it fcc} and $hcp$ structures of pure solid $para$-hydrogen. A CO molecule was then placed at different interstitial or substitution sites in large equilibrated {\it fcc} or $hcp$ $para$-hydrogen lattices, and the structural and dynamical behaviors of the micro-solvation environment around CO were simulated with a PIMC algorithm using a 2D effective $p$H$_2$-CO potential based on the 5D H$_2$--CO potential energy surface recently reported by Li {\it et al.},\footnote{\,H.\ Li, X-L.\ Zhang, R.\ J.\ Le Roy, and P.-N.\ Roy, {\em J.\ Chem.\ Phys.}\ {\bf 139}, 164315 (2013).} with a lattice sum of values of the 2D CO vibrational difference potential being use to predict the vibrational frequency shift. The effective rotational constants $B_{\rm eff}$ for CO in different solid $para$-hydrogen structures were also calculated and compared with the experimental observations and with predicted $B_{\rm eff}$ values for CO in large-sized $para$-hydrogen--CO clusters.\footnote{\,Y.\ Mizumoto and Y.\ Ohtsuki, {\em Chem.\ Phys.\ Lett.}\ {\bf 501}, 304 (2011).}~

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

English

Permalink

http://hdl.handle.net/2142/50789

DOI

https://doi.org/10.15278/isms.2014.FB07

Copyright and License Information

Copyright 2014 by the authors. Licensed under a Creative Commons Attribution 4.0 International License. http://creativecommons.org/licenses/by/4.0/

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