Near-infrared electronic spectroscopy of the HCCI A{sup 1}A{double_prime} {l_arrow} X{sup 1}A{prime} transition
- Brookhaven National Lab., Upton, NY (United States)
Rotationally resolved near-infrared spectra of the chloromethylene (HCCl) radical A{sup 1}A{double_prime} {l_arrow} X{sup 1}A{sup 1} transition were obtained at Doppler-limited resolution using a combination of laser transient absorption and radio frequency modulation (FM) techniques. Meter and Travis{close_quote} first reported the observation of the HCCl A {l_arrow} X bands, but were unable to rotationally resolve the A(0,1,0) {l_arrow} X(0,0,0) band and did not observe any other near-infrared bands due to their extreme weakness. Kakimoto et al. reported several laser-induced fluorescence (LIF) studies on the HCCl A{l_arrow}X bands at visible wavelengths, which correspond to the transitions terminating in the levels well above the barrier to linearity in the A and X states. In the present study, the authors have identified the transitions from the X(0,0,0) level to the A(0,0,0), A(0,1,0), and A(0,0,1) levels. The A(0,0,0) {l_arrow} X(0,0,0){sup 3} and A(0,0,1) {l_arrow} X(0,0,0) bands had not been previously observed. These observed A state levels are located below the barrier to linearity; i.e., the geometry in these levels is bent. Analysis has determined the geometry for the A(0,0,0) level: {angle}HCCl =134.7{degrees} and R(C-Cl)=1.623{Angstrom}. The authors have also found that the rotational structure is still perturbed by Renner-Teller effects resulting from interactions between the IR and k states which become degenerate at the linear configuration in a combination with spin-orbit interactions. A dispersed fluorescence experiment following excitation of a strong A{l_arrow}X transition in the visible is also in progress. The data from dispersed fluorescence spectra will shed light on the vibrational structure in the R state and probably will help to determine the singlet-triplet (X{sup 1}A{prime}-a{sup 3}A{double_prime}) separation. The details of the author`s experimental data and their analysis will be presented.
- Research Organization:
- Brookhaven National Laboratory (BNL), Upton, NY
- DOE Contract Number:
- AC02-76CH00016
- OSTI ID:
- 456881
- Report Number(s):
- CONF-9506113--
- Country of Publication:
- United States
- Language:
- English
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