TY - JOUR
T1 - Frequency-modulation transient absorption spectrum of the HCCl à 1A″(0,0,0)←X̃ 1A′(0,0,0) transition
AU - Chang, Bor Chen
AU - Sears, Trevor J.
PY - 1995
Y1 - 1995
N2 - The rotationally resolved spectrum of the HCCl à 1A″ (0,0,0)←X̃ 1A′(0,0,0) transition between 12 230 and 12 410 cm-1 was obtained for the first time at Doppler-limited resolution using a frequency-modulation (FM) transient absorption technique. Five major subbands (Ka=0→1, 1←0, 1←2, 2←1, and 2←3) of HC35Cl and one subband (Ka=0←1) of HC37Cl were observed and assigned. In addition, the forbidden subband (Ka=0←0) of HC35Cl 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 Ã(0,0,0) level: 〈HCCl=134.7° and RC-Cl=1.623 Å while RC-H is fixed at the corresponding value of CH2. The height of the barrier to linearity was found to be approximately 2170 cm-1 above the vibrationless level of the à state. The rotational structure of this spectrum shows irregular perturbations. Both random and J-dependent (anomalous 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.
AB - The rotationally resolved spectrum of the HCCl à 1A″ (0,0,0)←X̃ 1A′(0,0,0) transition between 12 230 and 12 410 cm-1 was obtained for the first time at Doppler-limited resolution using a frequency-modulation (FM) transient absorption technique. Five major subbands (Ka=0→1, 1←0, 1←2, 2←1, and 2←3) of HC35Cl and one subband (Ka=0←1) of HC37Cl were observed and assigned. In addition, the forbidden subband (Ka=0←0) of HC35Cl 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 Ã(0,0,0) level: 〈HCCl=134.7° and RC-Cl=1.623 Å while RC-H is fixed at the corresponding value of CH2. The height of the barrier to linearity was found to be approximately 2170 cm-1 above the vibrationless level of the à state. The rotational structure of this spectrum shows irregular perturbations. Both random and J-dependent (anomalous 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.
UR - http://www.scopus.com/inward/record.url?scp=0001649384&partnerID=8YFLogxK
U2 - 10.1063/1.1703016
DO - 10.1063/1.1703016
M3 - 期刊論文
AN - SCOPUS:0001649384
SN - 0021-9606
VL - 102
SP - 6347
EP - 6353
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
IS - 16
ER -