@article {4458,
	title = {Electronic spectra of YOH and YOD in the visible region: Strong vibronic coupling between the (B)over-tilde(1)II and (C)over-tilde(1)Sigma(+) states},
	journal = {Journal of Molecular Spectroscopy},
	volume = {196},
	number = {1},
	year = {1999},
	note = {ISI Document Delivery No.: 208RCTimes Cited: 7Cited Reference Count: 41},
	month = {Jul},
	pages = {45-69},
	type = {Article},
	abstract = {Laser excitation spectra of yttrium monohydroxide, YOH, have been recorded in the 500-625 nm wavelength region. Rotational analysis of bands of YOH and YOD has shown that the ground state is (X) over tilde(1)Sigma(+), with the structure r(0)(Y-O) = 1.948(6) Angstrom, r(0)(O-H) = 0.920(6) Angstrom; the bending frequency (nu(2), pi) is 313.73 cm(-1) (237.43 cm(-1) in YOD) and the Y-O stretching frequency (nu(3), sigma(+)) is 673.83 cm(-1) (655.34 cm(-1)). Two excited electronic states have been identified; they are assigned as (B) over tilde(1)Pi (16 449 cm(-1)) and (C) over bar(1)Sigma(+) (18 509 cm(-1)). Unusually strong vibronic coupling through the bending vibration occurs between these two states, which causes their vibrational structures to be highly irregular; assignments have only been possible following extensive wavelength-resolved fluorescence experiments. The vibronic coupling raises the bending frequency of the (C) over tilde(1)Sigma(+) state to 457 cm(-1) and reduces that of the lower Born-Oppenheimer component of the (B) over tilde(1)Pi state (which has A{\textquoteright} symmetry in the C, point group) to the extent that the molecule becomes nonlinear, with a potential barrier at the linear configuration of about 120 cm(-1). The presence of the potential barrier is clearly demonstrated by the level structure of YOD, where the Sigma(+) vibronic component of the 010 vibrational level (linear molecule notation) lies 1.4 cm(-1) below the 000 level. The upper Born-Oppenheimer component, which has A " symmetry, is unaffected; its bending frequency is similar to that of the ground state. Perturbations occur in both the (B) over tilde(1)Pi and (C) over tilde(1)Sigma(+) states; some of these represent local interactions between the two of them, but others are caused by higher vibrational levels of lower-lying "dark" electronic states. Over 40 ground state vibrational levels have been identified for both YOH and YOD from the wavelength-resolved fluorescence spectra. (C) 1999 Academic Press.},
	keywords = {15-K, laser spectroscopy, METHYLIDYNE, ORBITAL ANGULAR-MOMENTUM, RESONANCE, SYSTEM, TRANSITION, TRIATOMIC-MOLECULES, VANADIUM, WATER},
	isbn = {0022-2852},
	url = {<Go to ISI>://000081004300006},
	author = {Adam, A. G. and Athanassenas, K. and Gillett, D. A. and Kingston, C. T. and Merer, A. J. and Peers, J. R. D. and Rixon, S. J.}
}
