Universität zu Köln

Xu, Li-Hong, Lees, R. M., Crabbe, G. T., Myshrall, J. A., Mueller, H. S. P., Endres, C. P., Baum, O., Lewen, F., Schlemmer, S., Menten, K. M. and Billinghurst, B. E. (2012). Terahertz and far-infrared synchrotron spectroscopy and global modeling of methyl mercaptan, (CH3SH)-S-32. J. Chem. Phys., 137 (10). MELVILLE: AMER INST PHYSICS. ISSN 1089-7690

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Abstract

In this work, terahertz and Fourier transform far-infrared (FTFIR) synchrotron spectra of methyl mercaptan, CH3SH, have been investigated in order to provide new laboratory information for enhanced observations of this species in interstellar molecular clouds and star-forming regions. Like its methanol cousin, methyl mercaptan has particularly rich spectra associated with its large-amplitude internal rotation that extend throughout the THz and FIR regions. We have recorded new spectra for CH3SH from 1.1-1.5 and 1.790-1.808 THz at the University of Cologne as well as high-resolution FTFIR synchrotron spectra from 50-550 cm(-1) at 0.001 cm(-1) resolution on the far-IR beam-line at the Canadian Light Source. Assignments are reported for rotational quantum numbers up to J approximate to 40 and K approximate to 15, and torsional states up to nu(t) = 2 for the THz measurements and nu(t) = 3 for the FTFIR observations. The THz and FTFIR measurements together with literature results have been combined in a global analysis of a dataset comprising a total of 1725 microwave and THz frequencies together with similar to 18000 FTFIR transitions, ranging up to nu(t) = 2 and J(max) = 30 for MW/THz and 40 for FTFIR. The global fit employs 78 torsion-rotation parameters and has achieved a weighted standard deviation of similar to 1.1. A prediction list (nu(t) <= 2, J <= 45 and K <= 20) has been generated from the model giving essentially complete coverage of observable (CH3SH)-S-32 transitions within the bandwidths of major new astronomical facilities such as HIFI (Heterodyne Instrument for the Far Infrared) on the Herschel Space Observatory, ALMA (Atacama Large Millimeter Array), SOFIA (Stratospheric Observatory For Infrared Astronomy) and APEX (Atacama Pathfinder Experiment) to close to spectroscopic accuracy. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4745792]

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Xu, Li-Hong UNSPECIFIED UNSPECIFIED UNSPECIFIED Lees, R. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Crabbe, G. T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Myshrall, J. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mueller, H. S. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Endres, C. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Baum, O. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lewen, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schlemmer, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Menten, K. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Billinghurst, B. E. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-483016
DOI:	10.1063/1.4745792
Journal or Publication Title:	J. Chem. Phys.
Volume:	137
Number:	10
Date:	2012
Publisher:	AMER INST PHYSICS
Place of Publication:	MELVILLE
ISSN:	1089-7690
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language MILLIMETER-WAVE SPECTRUM; MOLECULAR-SPECTROSCOPY; MICROWAVE-SPECTRUM; COLOGNE DATABASE; METHANOL Multiple languages Chemistry, Physical; Physics, Atomic, Molecular & Chemical Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/48301