TOF mass spectra of (a) 1,2-C2H2Br2 and (b) 1,1-C2H2Br2 in the photolysis at 233 nm with the energy of 19 and 24 μJ/pulse, respectively. (c) The power dependence measurements of the Br+ and Br2 + signals dissociated from 1,2-C2H2Br2 at 233 nm.
The raw images of Br2 + and Br+ acquired from photodissociation of 1,2-C2H2Br2 and 1,1-C2H2Br2 at 233 nm. The color coding is also included.
Center-of-mass translational energy distributions of the Br2 + elimination channel from either 1,2-C2H2Br2 or 1,1-C2H2Br2 at 233 nm. The open circles are the experimental data and the solid lines are the fitted results.
Kinetic energy distributions of Br+ fragment upon dissociation of either 1,2-C2H2Br2 or 1,1-C2H2Br2 at 233 nm. The open circles are the experimental data that are deconvoluted into one Boltzmann and two Gaussian functions for 1,2-C2H2Br2, while one Boltzmann and one Gaussian functions for 1,1-C2H2Br2. The solid lines are the sum of fitted results.
Schematic diagram for probable photodissociation and photoionization pathways of dibromoethylenes (DBE) at 233 nm.
Ab initio calculations of dissociation pathways for the scheme, 1,2-C2H2Br2 → C2H2 + Br2 +. 1,2-C2H2Br2 contains both cis- and trans-isomers. The calculation level is B3LYP with the basis set 6-311**G(2df, 2pd).
Kinetic energy distributions of Br+ fragment dissociated from 1,2-C2H2Br2, when the laser is tuned to either a REMPI wavelength at 232.93 nm (dotted-line) or a non-REMPI wavelength at 233 nm (solid line). Their intensities are normalized.
Anisotropy parameters derived from the fragment images.
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