High resolution spectroscopy of the Ã1B1–A1 transition of CBr2

An ab Initio Investigation of Fluorobromo Carbene

“…Due to the numerous interactions between the electronic states, such as Renner–Teller effect, spin–orbit coupling, avoided crossing, or nonadiabatic interaction leading to predissociation, the spectroscopy and photodissociation dynamics of halocarbenes are rather complicated, which stimulate scientists to continuously perform experimental and theoretical studies on these important reactive intermediates. During past several decades, with the advances of high-resolution laser-based spectroscopic techniques along with theoretical methods, a variety of halocarbenes, including monohalogenated carbenes CHF − /CHCl − /CHBr − /CHI, dihalogenated carbenes CCl 2 , − CBr 2 , CFCl, CFBr, − and CFI, and so on, have been widely investigated by using, for example, rotational-resolved laser absorption, laser-induced fluorescence (LIF), optical–optical-double-resonance (OODR), and stimulated emission pumping (SEP) techniques, as well as ab initio calculations. − The structure, spectroscopy, and interactions of the ground state and the lowest singlet/triplet excited states of the halocarbenes have been studied comprehensively. Although sparse studies concerning higher excited states have emerged, for example, photodissociation dynamics of CHF and CDF at the B state, − CCl 2 at 248 nm , and 193 nm, and CHCl, CFCl, and CFBr at 193 nm …”

Theoretical Study on the Spectroscopic Properties and Photodissociation Mechanism of Dibromocarbene

“…Dissociation resulting in a loss of Br is particularly relevant to atmospheric ozone chemistry as the Br atom is much more destructive to ozone than the other halogen atoms − including the Cl atom. Bromine-containing halocarbons especially these bromine-substituted carbenes are the important subject of the experimental and theoretical studies in recent decades. − Herein, we focus on CBr 2 carbene.…”

“…As the special nature of the lowest singlet state and triplet state have been reported, information on the ground singlet state, the lowest triplet state, and energy separation between them is essential in understanding the chemistry of these halocarbons. Experimental − ,− and theoretical − investigations on the lowest three states and energy gaps between them (the à ← X̃ state adiabatic transition energy ( T 00 ) and the ã ← X̃ state adiabatic transition energy (S–T gap)) have been carried out in the past decades. However, the T 00 of CBr 2 are controversial as different groups have indicated that the T 00 are 14962 cm –1 , 14885 cm –1 , 15092 cm –1 , and 15278 cm –1 , by analysis of the laser-induced fluorescence spectra in the latest decades.…”