Rovibrational quantum dynamics of the methane-water dimer

Sarka, János

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https://hdl.handle.net/2142/96854 Copy

Description

Title

Rovibrational quantum dynamics of the methane-water dimer

Author(s)

Sarka, János

Contributor(s)

• Mátyus, Edit
• Császár, Attila

Issue Date

2017-06-20

Keyword(s)

• Large amplitude motions
• Internal rotation

Abstract

The challenging quantum dynamical description of the CH$_4$·H$_2$O complex has been solved variationallyfootnote{ J. Sarka, A. G. Császár, S. C. Althorpe, D. J. Wales and E. Mátyus, Phys. Chem. Chem. Phys. 18, 22816 (2016).}_x000d_ to provide theoretical explanation and assignment to the high-resolution spectroscopic measurements of the methane-water dimer carried out some twenty years ago.footnote{ L. Dore, R. C. Cohen, C. A. Schmuttenmaer, K. L. Busarow, M. J. Elrod, J. G. Loeser and R. J. Saykally, J. Chem. Phys. 100, 863 (1994).}_x000d_ The computational results are in excellent agreement with the reported experimental transitions and the experimentally observed reversed rovibrational sequences, i.e., formally negative rotational excitation energies, _x000d_ are also obtained in the computations. In order to better understand the origin of these peculiar features in the energy-level spectrum, we studiedfootnote{ J. Sarka, A. G. Császár and E. Mátyus, Phys. Chem. Chem. Phys. accepted for publication (2017).} _x000d_ all four possible combinations of the light and heavy isotopologues of methane and water and analyzed their rovibrational states using two limiting model systems:_x000d_ the rigidly rotating (RR) molecule and the coupled rotor (CR) system corresponding to the coupling of the two rotating monomers._x000d_ _x000d_ All rovibrational quantum dynamical computations$^{a,c}$ were carried out with rigid monomers and $J$ = 0,1,2 total angular momentum quantum numbers using the fourth-age quantum chemical code _x000d_ GENIUSHfootnote{ E. Mátyus, G. Czakó and A. G. Császár, J. Chem. Phys. 130, 134112 (2009).}$^{,}$footnote{C. Fábri, E. Mátyus and A. G. Császár, J. Chem. Phys. 134, 074105 (2011).}_x000d_ and two different methane-water potential energy surfaces_x000d_ (PES).footnote{O. Akin-Ojo and K. Szalewicz, J. Chem. Phys. 123, 134311 (2005).}$^{,}$footnote{C. Qu, R. Conte, P. L. Houston and J. M. Bowman, Phys. Chem. Chem. Phys. 17, 8172 (2015).}_x000d_ The numerical and formal analysis of the wave functions give insight into a fascinating complex world worth for further theoretical and experimental inquiries._x000d_ _x000d_ _x000d_ _x000d_ _x000d_ _x000d_ _x000d_ _x000d_ _x000d_ _x000d_ _x000d_ _x000d_

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/96854

DOI

https://doi.org/10.15278/isms.2017.TD05

Copyright and License Information

Copyright 2017 János Sarka

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