Infrared spectrum of cO-O2, a 'new' weakly-bound complex

McKellar, Bob

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https://hdl.handle.net/2142/91230 Copy

Description

Title

Infrared spectrum of cO-O2, a 'new' weakly-bound complex

Author(s)

McKellar, Bob

Contributor(s)

• Moazzen-Ahmadi, Nasser
• Michaelian, K. H.
• Barclay, A. J.

Issue Date

2016-06-22

Keyword(s)

Spectroscopy of Large Amplitude Motions

Abstract

• Only a few weakly-bound complexes containing the O$_{2}$ molecule have been characterized by high-resolution spectroscopy, notably N$_{2}$O-O$_{2}$ [1] and HF-O$_{2}$ [2]. This neglect is no doubt due in part to the complications added by the oxygen unpaired electron spin. Here we report an extensive infrared spectrum of CO-O$_{2}$, as observed in the CO fundamental band region ($\sim$2150 \wn) using a tunable quantum cascade laser to probe a pulsed supersonic jet expansion. The derived energy level pattern consists of ‘stacks’ characterized by $K$, the projection of the total angular momentum on the intermolecular axis. Five such stacks are observed in the ground vibrational state, and ten in the excited state, v(CO) = 1. They are divided into two groups, with no observed transitions between groups, and we believe these groups correlate with the two lowest rotational states of O$_{2}$, namely ($N$, $J$) = (1, 0) and (1, 2). In many ways, the spectrum and energy levels are similar to those of CO-N$_{2}$ [3], and we use the same approach for analysis, simply fitting each stack with its own origin, $B$-value, and distortion constants. The rotational constant of the lowest stack in the ground state (with $K$ = 0) implies an effective intermolecular separation of 3.82 \AA, but this should be interpreted with caution since it ignores possible effects of electron spin. \vskip 0.2 truecm [1] H.-B. Qian, D. Seccombe, and B.J. Howard, \textit{J. Chem. Phys.} \textbf{107}, 7658 (1997). [2] W.M. Fawzy, C.M. Lovejoy, D.J. Nesbitt, and J.T. Hougen, \textit{J. Chem. Phys.} \textbf{117}, 693 (2002)
• S. Wu, G. Sedo, E.M. Grumstrup, and K.R. Leopold, \textit{J. Chem. Phys.} \textbf{127}, 204315 (2007). [3] M. Rezaei, K.H. Michaelian, N. Moazzen-Ahmadi, and A.R.W. McKellar, \textit{J. Phys. Chem. A} \textbf{117}, 13752 (2013), and references therein.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

text

Language

En

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http://hdl.handle.net/2142/91230

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Copyright 2016 by the authors

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