Millimeter wave spectrum of bromomethyl radical, CH2Br.

Autor: Bailleux, Stéphane, Dréan, Pascal, Zelinger, Zdeneěk, Civiš, Svatopluk, Ozeki, Hiroyuki, Saito, Shuji
Předmět:
Zdroj: Journal of Chemical Physics; 4/1/2005, Vol. 122 Issue 13, p134302, 6p, 4 Charts, 2 Graphs
Abstrakt: The rotational spectra of the two isotopic species of the bromomethyl radical, CH279Br and CH281Br, have been observed in their ground electronic state 2B1 in the 180–470 GHz frequency region, corresponding to a-type transitions from N=8-7 to N=21-20. The radical was produced by hydrogen abstraction of methylbromide (CH3Br) either by chlorine or by fluorine atoms in a free space cell. Hyperfine structure due to the bromine nucleus has been resolved in the observed spectra, and the rotational constants as well as the fine and hyperfine interaction constants were accurately determined for both isotopomers. The inertial defect was determined to be 0.028 96(20) and 0.028 95(20) amu Å2, for CH279Br and CH281Br, respectively, suggesting a planar structure. By fixing the ∠HCH bond angle at 124.5°, an effective molecular structure can be derived as r0(CBr)=1.848 Å and r0(CH)=1.084 Å. A comparison of the molecular structure of various halogen-substituted methyl radicals with respect to the planarity of these radicals is discussed. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index