Production of Halomethylenes in Free-Jet Expansions from a Hot Nozzle: Identification and Characterization of HCBr and DCBr by Laser-Induced Fluorescence Excitation Spectroscopy

Vibronic Reassignment of theÃ1A′′ ←X̃1A′ Band System of Bromomethylene

“…They identified transitions at shorter wavelengths terminating at higher bending vibrational levels of the excited state. However, the position of the à 1 AЉ(020) level of DCBr we determined, although appearing to agree with the estimated position of the à 1 AЉ state zero point level extrapolated from the HCBr results, did not agree with the positions of higher bending of DCBr levels that could be determined from the assignments made by XBH (6).…”

“…XBH determined approximate values for the à state Ј 3 of 783 and 769 cm Ϫ1 for HCBr and DCBr, respectively (6). A similar small difference in the C-Br stretching frequency would be expected for the X state, and hence, a value for Љ 3 Ϸ 669 cm Ϫ1 for DCBr was assumed.…”

“…An approximate value of Љ 3 ϭ 683 cm Ϫ1 has been determined (7). f Band systems observed in LIF studies (6,12). The excited state bending quantum number assignments are reduced by one from those given in the previous work.…”

Visible Wavelength Electronic Spectroscopy of the DCBr ÖX̃ Vibronic Transition

“…Three of the four were first reported by Xu et al (8) and their vibronic assignments were later revised by Marr and Sears (15). According to the new assignments (15), these bands correspond to the transitions from the ground state zero-point level to theà state (0,9,0), (0,8,0), and (0,7,1) levels.…”

“…Xu et al (8) reported the first measurements on theà ←X vibronic spectrum of HCBr and DCBr at visible wavelengths using laser-induced fluorescence (LIF) in a pyrolysis free jet expansion source. Sears and co-workers (6,7,(9)(10)(11)(12) reported the rotationally resolved electronic spectrum of HCBr/DCBr in the near-infrared (NIR) region using laser absorption techniques and observed complicated perturbations in the high resolution spectrum.…”