Time resolved Diode Laser Spectroscopy of the $\nu_{1}$ Band of the Monocarbonyliron Radical (FeCO)
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Date
1995
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Publisher
Ohio State University
Abstract
The $\nu_{1}$ (CO stretch) fundamental band of FeCO, which is a linear radical with the $X^{3}\Sigma$ ground electronic state, was observed by time-resolved infrared diode laser spectroscopy. The FeCO radical was produced by the photolysis of pentacarbonyliron $Fe(CO)_{s}$ with 193 nm ArF excimer laser light. More than 90 absorption lines have been assigned to the $\nu_1$ fundamental band of FeCO including the $F_{1}, F_{2}$ and $F_{3}$ spin components in the 1935-70 cm region. Several lines, observed as doublet due to the t-type splitting, were assigned to the hot band from the $\nu_{2} (bend {\sim}330 cm^{-1})$ state. The lifetime of FeCO was about 0.5 msec in the present condition. The rotational and spin-spin interaction constants of the ground state. $B_{O} = 4364.92(13) MHz, D_{0}=2.481(41) kHz$, and $\lambda_{0} = 532.49(91) GHz$, as well as those for the $\nu_{1}$ state are derived from the diode laser spectrum combined with the rotational spectrum in the $F_{1}$ substate of the ground state by FTMW spectroscopy (1). The vibrational band origin obtained $1946.469 43(35) cm^{-1}$ is consistent with the value by the photoelectron spectroscopy of the FeCO negative ion. $1950\pm10 cm^{-1}$ (2). A number of spectral lines were observed in the region of $1935-60 cm^{-1}$ which are likely due to the degenerate CO stretch band of the $Fe(CO)_{3}$ species.
Description
(1) Y. Kasai, Y. Ohshima, and Y. Endo, private communication. (2) P.W. Villalta and D.G. Leopold, J. Chem. Phys., 98, 7730 (1993).
Author Institution: "Faculty of Science, Kyushu University", 33 Hakozaki, Higashiku, Fukuoka 812-81, Japan.
Author Institution: "Faculty of Science, Kyushu University", 33 Hakozaki, Higashiku, Fukuoka 812-81, Japan.