Universität zu Köln

Fortenberry, Ryan C., Lee, Timothy J. and Mueller, Holger S. P. (2015). Excited vibrational level rotational constants for SiC2: A sensitive molecular diagnostic for astrophysical conditions. Mol. Astrophys., 1. S. 13 - 20. AMSTERDAM: ELSEVIER. ISSN 2405-674X

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Abstract

Silacyclopropynylidene, SiC2, is a known and highly abundant circumstellar molecule. Its spectrum has been established as a major component of lines observed toward the carbon-rich star IRC +10216 (CW Leonis). It has been detected in its low-lying v(3) = 1 and 2 vibrational states as well as in various isotopic compositions. Increasing sensitivity and spatial resolution will enable many more emission or absorption lines to be detected. In order to detect new molecular species, unassigned lines of known species must be identified. This work uses established alpha b initio quartic force fields to produce data necessary for this classification of lines related to SiC2. Agreement between the theoretical vibrational frequencies and known rotational and spectroscopic constants is quite good, as good as 5 cm and 3 MHz, respectively in some cases. In addition, experimentally unknown vibrational frequencies and rotational constants are provided for the first overtones and combination bands in addition to 313, the second overtone of the low-lying antisymmetric stretch/carbide rotation mode. Frequencies of v(3) = 3 low-J rotational transitions of the main isotopic species are also estimated from published data for v(3) <= 2. Further, we determine rotational and centrifugal distortion parameters for which in most cases vibrational effects due to the v(3) mode were reduced to first, and in several cases also to second order. These values may approximate equilibrium values better than the ground state values. The data produced herein will aid in the experimental and observational characterization of this known astromolecule in order to identify some of the unassigned lines fora known entity. (C) 2015 Elsevier B.V. All rights reserved.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Fortenberry, Ryan C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lee, Timothy J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Mueller, Holger S. P. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-388894
DOI:	10.1016/j.molap.2015.07.001
Journal or Publication Title:	Mol. Astrophys.
Volume:	1
Page Range:	S. 13 - 20
Date:	2015
Publisher:	ELSEVIER
Place of Publication:	AMSTERDAM
ISSN:	2405-674X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SPECTROSCOPIC PARAMETERS; LINE SURVEY; BASIS-SETS; FREQUENCIES; ENERGY; EXCITATION; IRC+10216; GEOMETRY Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/38889