ELECTRONIC BANS SYSTEMS OF VCH IN THE 590-800 nm REGION
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Date
1994
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
A complicated system of about 30 bands in the 590-800 nm region has been discovered by laser excitation, following the reaction of laser-ablated vanadium atoms with methane under supersonic jet-cooled conditions. At least two electronic transitions must be present, since the most prominent bands are analysed so far have integer rotational quantum numbers, and clear ${^{51}}V$ nuclear hyperfine structure. The presence of hydrogen in the carrier is suggested by experiments with $CD_{4}$. but the simple linear-molecule sub-band structure indicates that the carrier is VCH, rather than $VCH_{3}$. The lower state of the strongest bands in an $\Omega = 1$ state, presumably $X_{3} \Delta_{1}$ by analogy with $VN^{1}$. Wavelength resolved fluorescence experiments reveal a highly structured vibrational level pattern in the ground state, with the most prominent peaks corresponding to levels at 146, 572, 840, 1118 and $1402 cm^{-1}$ frequency is probably the V-C stretching vibration, shifted down considerably from its value in the isoelectronic VN molecule. Consistent with this, rotational analysis has given $B^{\prime\prime} = 0$. $491 cm^{-1}$, which correspond to a V-C bond length of about 1.72 {\AA}, some some 0.15 A longer than in VN while the hypergine h parameter of the ground state $(-0.0083 cm^{-1})$ is less than half that of VN, The 572 and $1118 cm^{-1}$ levels seem to involve overtones of the bending vibration, distorted by orbital angular momentum effects, while the $146 cm^{-1}$ interval is provisionally assigned as the lowest spin-orbit interval of the ground state. Rotational perturbations are widespread throughout the system. cvcn in the bands near 800 nm. While the A-doubling in the $({^{3}}\Pi_{0}$) upper state of the 639 nm band is highly erratic.
Description
1. W.J. Balfour, A.J. Merer, H. Niki, B. Simard and P.A. Hackett, J. Chem Phys. 99, 3288 (1993).
Author Institution: Department of Chemistry, University of British Columbia; Department of Chemistry, University of Waterloo
Author Institution: Department of Chemistry, University of British Columbia; Department of Chemistry, University of Waterloo