193 nm photolysis of vinyl bromide: Nascent product distribution of the C2H3Br→C2H2 (vinylidene)+HBr channel

Abstract

Three-center versus four-center elimination in photolysis of vinyl fluoride and vinyl bromide at 193 nm: Bimodal rotational distribution of HF and HBr (v5) detected with time-resolved Fourier transform spectroscopy J. Chem. Phys. 114, 7396 (2001); 10.1063/1.1343079 I. Three-center versus four-center HCl-elimination in photolysis of vinyl chloride at 193 nm: Bimodal rotational distribution of HCl (v7) detected with time-resolved Fourier-transform spectroscopyThe internal energy content of the photofragments HBr and C 2 H 2 from the minor channel of the photolysis of C 2 H 3 Br with 193 nm radiation has been measured using time-resolved infrared Fourier transform IR emission spectroscopy with 0.5 s resolution. Vibrational level population and the rotational population of the HBr fragment are determined from 1.0 s following the photolysis until complete HBr relaxation. The nascent distribution of HBr is extrapolated, from a collision quenching model with a Boltzmann distribution, to be at 8690 and 7000 K for the vibration and rotation respectively. The product vibrational energy distribution supports a reaction mechanism based on the 3-centered HBr elimination process yielding vinylidene and HBr. The nascent internal energy of vinylidene is deduced to be 24 kcal/mol. Vinylidene isomerizes to acetylene and the acetylene emission bands, 3 , 4 ϩ 5 and 5 , are detected.

Theoretical investigation of the dissociation dynamics of vibrationally excited vinyl bromide on an ab initio potential-energy surface obtained using modified novelty sampling and feedforward neural networks. II. Numerical application of the method

“…24 All these results are in excellent accord. Branching ratios into each of the open reaction channels are reported so that rate coefficients into each channel may be determined.…”

FTIR and Raman Spectroscopy Study of Soot Deposits Produced in the Infrared Multiphoton Dissociation of Vinyl Bromide

“…e transitions of vibrationally excited hydrogen bromide HBr (1-3) have been attributed to the bands occurring between 2,400 cm -1 and 2,700 cm −1 [61,62,64]. Furthermore, a solid deposit has been seen clinging to the cell walls and windows.…”

“…Along with the decrease in the bands belonging to the BrV, additional bands appear with the original spectrum, showing that the BrV has decoupled, as can be seen in the spectrum obtained after the irradiation. e bands at 730 cm −1 and 3,270 cm −1 , attributed to the torsional vibrations of the CH bond of the five modes and the three asymmetric CH stretch modes, respectively, have been recognized as belonging to acetylene (C 2 H 2 ) [61][62][63].…”

Photodissociation transition states characterized by chirped pulse millimeter wave spectroscopy

“…Photolysis of ethylene (13) and its substituted analogs, VCN (12,22,(46)(47)(48)(49)(50)(51)(52), vinyl chloride (15,23,25,26), vinyl bromide (17,24,53,54), vinyl iodide (55), and propene (56), has been extensively studied during the last 4 decades. The 193-nm photolysis (57) of VCN has been observed (12,22,43,47,49) and calculated (43,48,50,52) to take place via a dizzying array of reaction pathways.…”