THE ROTATIONAL SPECTRA OF {sup 29}SiC{sub 2} AND {sup 30}SiC{sub 2}

Journal Article · Sat Oct 01 04:00:00 EDT 2011 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.1088/0067-0049/196/2/17· OSTI ID:21560325

Kokkin, D L ^[1]; Bruenken, S; Young, K H; Patel, N A; Gottlieb, C A; Thaddeus, P

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1. School of Chemistry, University of Sydney, NSW 2006 (Australia)

The rotational spectra of {sup 29}SiC{sub 2} and {sup 30}SiC{sub 2}, two silicon isotopic species of the abundant astronomical ring {sup 28}SiC{sub 2}, have been characterized in the millimeter band between 140 and 360 GHz in a low pressure discharge through SiH{sub 4}, C{sub 2}H{sub 2}, and Ar. Precise rotational and centrifugal distortion constants have been derived for both species by fitting a standard asymmetric top Hamiltonian to 38 a-type transitions of {sup 29}SiC{sub 2} and 35 of {sup 30}SiC{sub 2}; the data sets include transitions up to K{sub a} = 8 and at least J = 16. With these new measurements in hand, the most intense radio transitions of both species either have been measured or can now be predicted to better than 1 km s{sup -1} in equivalent radial velocity up to 500 GHz, more than adequate accuracy for spectral line identifications in circumstellar shells of evolved carbon stars such as IRC+10216 where SiC{sub 2} is conspicuous. More than 10 new lines of {sup 29}SiC{sub 2} and {sup 30}SiC{sub 2} have been identified between 295 and 354 GHz in the interferometric spectral line survey of IRC+10216 with the Submillimeter Array.

• OSTI ID: 21560325
• Journal Information: Astrophysical Journal, Supplement Series, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 2 Vol. 196; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
CARBIDES
CARBON COMPOUNDS
CARBON STARS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EVEN-EVEN NUCLEI
EVEN-ODD NUCLEI
EXCITED STATES
HAMILTONIANS
ISOTOPES
LIGHT NUCLEI
MAIN SEQUENCE STARS
MATHEMATICAL OPERATORS
NUCLEI
QUANTUM OPERATORS
ROTATIONAL STATES
SILICON 29
SILICON 30
SILICON CARBIDES
SILICON COMPOUNDS
SILICON ISOTOPES
SPECTRA
STABLE ISOTOPES
STARS