Frequency-modulation transient absorption spectrum of the HCCl {ital {tilde A}} {sup 1}{ital A}{double_prime}(0,0,0){l_arrow}{ital {tilde X}} {sup 1}{ital A}{prime}(0,0,0) transition
- Department of Chemistry, Brookhaven National Laboratory, Upton, New York 11973-5000 (United States)
The rotationally resolved spectrum of the HCCl {ital {tilde A}} {sup 1}{ital A}{double_prime}(0,0,0){l_arrow}{ital {tilde X}} {sup 1}{ital A}{prime}(0,0,0) transition between 12 230 and 12 410 cm{sup {minus}1} was obtained for the first time at Doppler-limited resolution using a frequency-modulation (FM) transient absorption technique. Five major subbands ({ital K}{sub {ital a}}=0{l_arrow}1, 1{l_arrow}0, 1{l_arrow}2, 2{l_arrow}1, and 2{l_arrow}3) of HC{sup 35}Cl and one subband ({ital K}{sub {ital a}}=0{l_arrow}1) of HC{sup 37}Cl were observed and assigned. In addition, the forbidden subband ({ital K}{sub {ital a}}=0{l_arrow}0) of HC{sup 35}Cl was also observed. Thus far, we have assigned most (more than 70%) of the strong lines. The analysis of these subbands determines the geometry for the HCCl {ital {tilde A}}(0,0,0) level: {angle}HCCl=134.7{degree} and {ital R}{sub C-Cl}=1.623 A while {ital R}{sub C-H} is fixed at the corresponding value of CH{sub 2}. The height of the barrier to linearity was found to be approximately 2170 cm{sup {minus}1} above the vibrationless level of the {ital {tilde A}} state. The rotational structure of this spectrum shows irregular perturbations. Both random and {ital J}-dependent (anomalous {ital K}-type doubling) effects were observed. As in methylene, the perturbations most likely arise from Renner--Teller effect between the two singlet states in combination with spin--orbit coupling between the singlet and triplet states.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 29270
- Journal Information:
- Journal of Chemical Physics, Vol. 102, Issue 16; Other Information: PBD: 22 Apr 1995
- Country of Publication:
- United States
- Language:
- English
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