Photodissociation of CH2BrI using cavity ring-down spectroscopy: in search of a BrI elimination channel

摘要

Photodissociation of CH2BrI was investigated in search of unimolecular elimination of BrI via a primary channel using cavity ring-down absorption spectroscopy (CRDS) at 248 nm. The BrI spectra were acquired involving the first three ground vibrational levels corresponding to A(3)pi(1) <- X-1 sigma(+) transition. With the aid of spectral simulation, the BrI rotational lines were assigned. The nascent vibrational populations for v '' = 0, 1, and 2 levels are obtained with a population ratio of 1 : (0.58 +/- 0.10) : (0.34 +/- 0.05), corresponding to a Boltzmann-like vibrational temperature of 713 +/- 49 K. The quantum yield of the ground state BrI elimination reaction is determined to be 0.044 +/- 0.014. The CCSD(T)//B3LYP/MIDI! method was employed to explore the potential energy surface for the unimolecular elimination of BrI from CH2BrI.