The millimeter-wave spectrum of NiC (Χ1Σ+) and CoC (Χ2Σ+)

M. A. Brewster, Lucy M Ziurys

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Abstract

The pure rotational spectra of two metal carbide species, NiC (Χ1Σ+) and CoC (Χ2Σ+), have been measured in the laboratory using millimeter/submillimeter direct absorption methods. The molecules were created by reacting metal vapor with CH4 in a DC discharge. Four rotational transitions of CoC were recorded, each consisting of 16 hyperfine components arising from the cobalt nuclear spin of I = 7/2. Multiple transitions of the two most abundant nickel isotopomers, 58NiC and 60NiC, were additionally measured. The spectra were analyzed using the appropriate Hamiltonian and spectroscopic constants accurately determined. For CoC, this study included a complex hyperfine analysis of the magnetic, electric quadrupole, and nuclear spin-rotation terms. Cobalt and nickel are iron peak elements that may be produced via neutron capture processes in asymptotic giant branch stars. Dredge-up events mix these elements to the stellar surface, where they are incorporated into the expanding stellar envelope. CoC and NiC offer a means to trace these elements in carbon-rich circumstellar shells.

Original languageEnglish (US)
JournalAstrophysical Journal
Volume559
Issue number2 PART 2
DOIs
Publication statusPublished - Oct 1 2001
Externally publishedYes

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Keywords

  • ISM: molecules
  • Line: identification
  • Methods: laboratory
  • Molecular data

ASJC Scopus subject areas

  • Space and Planetary Science

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