Victoria H.J. Clark
The vibrational properties of benzene on an ordered water ice surface
Clark, Victoria H.J.; Benoit, David M.
We present a hybrid CCSD(T) + PBE-D3 approach to calculating the vibrational signatures for gas-phase benzene and benzene adsorbed on an ordered water ice surface. We compare the results of our method against experimentally recorded spectra and calculations performed using PBE-D3-only approaches (harmonic and anharmonic). Calculations use a proton ordered XIh water ice surface consisting of 288 water molecules, and results are compared against experimental spectra recorded for an ASW ice surface. We show the importance of including a water ice surface into spectroscopic calculations, owing to the resulting differences in vibrational modes, frequencies, and intensities of transitions seen in the IR spectrum. The overall intensity pattern shifts from a dominating ν11 band in the gas-phase to several high-intensity carriers for an IR spectrum of adsorbed benzene. When used for adsorbed benzene, the hybrid approach presented here achieves an RMSD for IR active modes of 21 cm-1, compared to 72 cm-1 and 49 cm-1 for the anharmonic and harmonic PBE-D3 approaches, respectively. Our hybrid model for gaseous benzene also achieves the best results when compared to experiment, with an RMSD for IR active modes of 24 cm-1, compared to 55 cm-1 and 31 cm-1 for the anharmonic and harmonic PBE-D3 approaches, respectively. To facilitate assignment, we generate and provide a correspondence graph between the normal modes of the gaseous and adsorbed benzene molecules. Finally, we calculate the frequency shifts, Δν, of adsorbed benzene relative to its gas-phase to highlight the effects of surface interactions on vibrational bands and evaluate the suitability of our chosen dispersion-corrected density functional theory.
Clark, V. H., & Benoit, D. M. (2021). The vibrational properties of benzene on an ordered water ice surface. Monthly notices of the Royal Astronomical Society, 508(3), 3239-3250. https://doi.org/10.1093/mnras/stab2670
|Journal Article Type||Article|
|Acceptance Date||Sep 10, 2021|
|Online Publication Date||Sep 20, 2021|
|Deposit Date||May 19, 2022|
|Publicly Available Date||May 27, 2022|
|Journal||Monthly Notices of the Royal Astronomical Society|
|Publisher||Oxford University Press|
|Peer Reviewed||Peer Reviewed|
|Keywords||Astrochemistry; Molecular data; Dust; Extinction; ISM: molecules; Infrared: ISM|
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2021 The Author(s)Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
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