Spectra of C6H6-Rgn (n=1,2) in the 3 mircon infrared band system of benzene

Moazzen-Ahmadi, Nasser

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https://hdl.handle.net/2142/100505 Copy

Description

Title

Spectra of C6H6-Rgn (n=1,2) in the 3 mircon infrared band system of benzene

Author(s)

Moazzen-Ahmadi, Nasser

Contributor(s)

• McKellar, Bob
• Barclay, A. J.

Issue Date

2018-06-18

Keyword(s)

Clusters/Complexes

Abstract

Benzene-noble gas complexes were one of the earliest topics of interest in spectroscopic investigation of van der Waals (vdW) complexes. Smalley et al.a observed C6H6-(He)1,2 vdW complexes in the late 1970s by means of electronic spectroscopy. A recent study on the same species was done by Hayashi and Oshimab at higher resolution (250 MHz). Here, we present an extensive infrared observation of C6H6-Rgn (n=1,2) with the rare gas being He, Ne, or Ar, in the 3 micron region. The spectra were observed using a tunable optical parametric oscillator to probe a pulsed supersonic-jet expansion from a slit nozzle. Benzene monomer is known to have a complex band system in this region.c The strongest band, centered around 3047.91 cm−1 , belongs mainly to the C-H stretching fundamental ν12 of symmetry E1u. Other strong perpendicular bands occurring just above the main band as a result of intensity borrowing via anharmonic resonances between the fundamental ν12 and the combinations are ν2 + ν13 + ν18, occurring near 3079 cm−1 , and ν13 + ν16 and ν3 + ν10 + ν18, both occurring near 3100 cm−1 . The latter two bands are separated by merely 1.45 cm−1 . Although data analysis and observation are presently ongoing, we observe analogous bands for C6H6-Rgn (n=1,2). Spectra were assigned to a symmetric top with C6v symmetry with the rare gas atom being located on the C6 symmetry axis. Spectra of the C6H6-Rg2 trimers are in agreement with a D6h symmetry structure, where the rare gas atoms are positioned above and below the plane of the Benzene monomer. Although jet conditions have resulted in excellent signal to noise for the dimer and trimer spectra, we have not been able to identify any lines which might be due to tetramers or larger clusters. We intend to pursue the search for large clusters using a cooled nozzle.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

eng

Permalink

http://hdl.handle.net/2142/100505

DOI

10.15278/isms.2018.MK04

Copyright and License Information

Copyright 2018 Nasser Moazzen-Ahmadi

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