University of Illinois Urbana-Champaign

TERAHERTZ SPECTROSCOPY OF DEUTERATED METHYLENE BI-RADICAL, CD2

Bailleux, Stephane

Content Files
296169.pptx
807.pdf

Permalink

https://hdl.handle.net/2142/79106

Description

Title
TERAHERTZ SPECTROSCOPY OF DEUTERATED METHYLENE BI-RADICAL, CD2
Author(s)
Bailleux, Stephane
Contributor(s)
Ozeki, Hiroyuki
Issue Date
25-Jun-15
Keyword(s)
Astronomy
Date of Ingest
2016-01-05T20:04:34Z
Abstract
setlength{belowdisplayskip}{3pt} setlength{abovedisplayskip}{2pt} Methylene, the parent of the carbene compounds, plays a crucial role in many chemical reactions. This bi-radical is a known interstellar molecule that has been detected towards hot cores in dense interstellar clouds. CH$_2$ is also thought to be present in cometary atmospheres. In the gas phase chemical models of both dense and diffuse molecular clouds, CH$_2$ is a key intermediate in interstellar carbon chemistry which is produced primarily by dissociative recombination of the methyl ion, CH$^+_3$. Recently tentative detection of the mono-deuterated methyl ion, CH$_2$D$^+$ has been reported toward an infrared source in the vicinity of Orion.footnote{D. C. Lis, P. F. Goldsmith, E. A. Bergin et al. 2009, in Submillimeter Astrophysics and Technology, ASP Conf. Ser., 417, 23.} Deuterated methylene CHD and CD$_2$ can be produced from this ion or its counterpart CHD$^+_2$ by dissociative recombination with an electron: begin{equation} mathrm{CH_{2}D^{+} + e^{-} rightarrow CHD+ H ~or~{CH_{2} + D}}, end{equation} begin{equation} mathrm{CHD_{2}^{+} ~~+ e^{-} rightarrow CHD+ D ~or~CD_{2} + H}. end{equation} Thus, both CHD and CD$_2$ can be observed in warm interstellar clouds, where the deuterium fractionation process is important. Precise laboratory reference data are desirable for radioastronomical observation of these molecules. Here we report on our high-resolution spectroscopic investigation on the deuterated methylene radical, CD$_2$ ($X$ $^3$B$_1$) up to 1.45 THz. At present time, eleven out of the twelve fine-structure components of four pure rotational transitions have been newly recorded, and these measurements double the number of previously observed transitions.footnote{H. Ozeki and S. Saito J. Chem. Phys. 1996, 104, 2167.} CD$_2$ was generated in a discharge in CD$_2$CO which was obtained from the flash pyrolysis of acetic anhydride-d6 ((CD$_3$CO)$_2$O). Effort is currently made to measure the astronomically important $1_{11} - 0_{00}$ transition whose fine-structure components are predicted to occur at 1.224,1.228 and 1.234 THz.
Publisher
International Symposium on Molecular Spectroscopy
Type of Resource
text
Genre of Resource
Conference Paper / Presentation
Language
English
Permalink
http://hdl.handle.net/2142/79106

Owning Collections

Abstracts & Presentations - 2015 International Symposium on Molecular Spectroscopy PRIMARY