Time-resolved Diode Laser Spectroscopy of the $\nu_{6}$ Band of the Propargyl Radical
Loading...
Date
1994
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
The $\nu_{6}$ ($CH_{2}$ wagging) fundamental band of the propargyl radical ($CH_{2}C=CH$) was observed by time-resolved infrared diode laser spectroscopy. The propargyl radical was produced by the photolysis of allene $(C_{3}H_{4})$ or propargyl chloride ($ClCH_{3}C-CH$) with 193 nm ArF excimer laser light. More than 120 absorption lines have been assigned to the $v_{6}$ fundamental band of propargyl including $K_{a}=1 \leftarrow 0, 0 \leftarrow 1, 2 -1, 1 \leftarrow 2$, and $3 \leftarrow 4$ subbands. Most of the absorption lines were observed as doublets due to the spin-rotation interaction in the ${^{2}}B_{1}$ ground electronic state. The rotational and spin-rotation constants for the ground state. $A = 288045.5(34), \widetilde{B} = 9365.2766(73), B-C - 316, 30 (23) \varepsilon_{\infty} -544.2(29), \varepsilon_{bb}-11.043(37)$, and $\varepsilon{\infty}=-1.0$ (fixed) MHx, are derived from the diode laser spectrum combined with the $1_{0.1} \leftarrow O_{0.0}$ rotational spectrum by FTMW spectroscopy (1). The vibrational band origin obtained is $687.174.89(63) cm^{-1}$, which is consistent with the infrared spectrum observed in the argon matrix (2). The molecular constants for the $\nu_{6}$ state are largely affected by the $\alpha$-type Coriolis interaction with the $v_{10} (CH_{2}$ rocking) vibration, for example, the rotational and the centrifugal distortion constants A and $\Delta k$ in the $v^{6}$ state change by $-13440(23)$ and $-24.2(21)$ MHz, respectively, from those of the ground state. The figures in parentheses are standard deviation to be attached to the last digit.
Description
(1) K. Tanaka, Y. Ohshima, and Y. Endo, to be published. (2) M. E. Jacox and D. E. Milligan. Chem. Phys., 4, 45-61 (1974).
Author Institution: Department of Chemistry, Faculty of Science, Kyushu University 33, Hakozaki
Author Institution: Department of Chemistry, Faculty of Science, Kyushu University 33, Hakozaki