@article {2996,
	title = {SUB-DOPPLER SPECTROSCOPY OF THIOFORMALDEHYDE - EXCITED-STATE PERTURBATIONS AND EVIDENCE FOR ROTATION-INDUCED VIBRATIONAL MIXING IN THE GROUND-STATE},
	journal = {Journal of Chemical Physics},
	volume = {101},
	number = {9},
	year = {1994},
	note = {ISI Document Delivery No.: PP519Times Cited: 9Cited Reference Count: 50},
	month = {Nov},
	pages = {7300-7310},
	type = {Article},
	abstract = {High-resolution intracavity dye laser spectroscopy has been used to obtain sub-Doppler spectra of transitions to 350 rotational levels in the 4(0)(1) band of the ($) over tilde A (1)A(2)-($) over tilde X (1)A(1) electronic transition of thioformaldehyde. Ground state combination differences from the sub-Doppler spectra, combined with microwave and infrared data, have been used to improve the ground state rotational and centrifugal distortion constants of H2CS. The upper state shows a remarkable number of perturbations. The largest of these are caused by nearby triplet levels, with matrix elements of 0.05-0.15 cm(-1). A particularly clear singlet-triplet avoided crossing in K-a{\textquoteright} = 7 has been shown to be caused by interaction with the F-1 component of the 3(1)6(2) vibrational level of the ($) over tilde a (3)A(2) state. At least 53\% of the S-1 levels show evidence of very small perturbations by high rovibronic levels of the ground state. The number of such perturbations is small at low J, but increases rapidly beyond J=5 such that 40\%-80\% of the observed S-1 levels of any given J are perturbed by ground state levels. Model calculations show that the density and J dependence of the number of perturbed levels can be explained if there is extensive rotation-induced mixing of the vibrational levels in the ground state.},
	keywords = {ANTICROSSING SPECTROSCOPY, HIGH ROVIBRONIC LEVELS, HIGH-RESOLUTION, LASER, LEVEL, OPTICAL DOUBLE-RESONANCE, POLYATOMIC-MOLECULES, POTENTIAL-ENERGY, PYROLYSIS JET SPECTROSCOPY, QUANTUM BEAT SPECTROSCOPY, SINGLET-TRIPLET PERTURBATIONS, SPECTROSCOPY, SURFACES},
	isbn = {0021-9606},
	url = {<Go to ISI>://A1994PP51900012},
	author = {Clouthier, D. J. and Huang, G. and Adam, A. G. and Merer, A. J.}
}
@article {7202,
	title = {A SPECTROSCOPIC VIEW OF INTERNAL-CONVERSION IN A SMALL POLYATOMIC MOLECULE - SUB-DOPPLER INTRACAVITY DYE-LASER SPECTROSCOPY OF THIOFORMALDEHYDE},
	journal = {Journal of Chemical Physics},
	volume = {97},
	number = {3},
	year = {1992},
	note = {ISI Document Delivery No.: JE891Times Cited: 4Cited Reference Count: 28},
	month = {Aug},
	pages = {1630-1637},
	type = {Article},
	abstract = {Intracavity dye laser spectroscopy has been used to obtain sub-Doppler spectra of selected rotational lines in the A approximately 1A2-X approximately 1A1 4(0)1 band of thioformaldehyde with very high resolution and sensitivity. Many of the spectra show extra lines due to perturbations involving high vibrational levels of the ground state. Most of the perturbations observed for K(a){\textquoteright} = 0 and 4 are found to correlate well with previous observations of anomalously long single rotational level fluorescence lifetimes and reduced quantum yields [J. Dunlop and D. J. Clouthier, J. Chem. Phys. 93, 6371 (1990)]. S1-S0 interaction matrix elements of 0.001-0.006 cm-1 are found for levels involved in simple two level perturbations. The large number of small random perturbations by levels of the ground state is indicative of the first stages of the onset of quantum chaos in a small molecule. Some larger perturbations in the rotational structure are also observed; these are caused by additional local interactions with levels of the nearby triplet state.},
	keywords = {A1A2 EXCITED-STATE, FORMALDEHYDE, lifetimes, MAGNETIC, OPTICAL DOUBLE-RESONANCE, ROTATION SPECTRUM, ROVIBRONIC LEVELS, SINGLET-TRIPLET PERTURBATIONS, TRANSITIONS, TRILET PERTURBATIONS, VISIBLE ABSORPTION SYSTEM},
	isbn = {0021-9606},
	url = {<Go to ISI>://A1992JE89100003},
	author = {Clouthier, D. J. and Huang, G. and Merer, A. J.}
}
