Predicting the effect of angular momentum on the dissociation dynamics of highly rotationally excited radical intermediates.

We present a model which accurately predicts the net speed distributions of products resulting from the unimolecular decomposition of rotationally excited radicals. The radicals are produced photolytically from a halogenated precursor under collision-free conditions so they are not in a thermal distribution of rotational states. The accuracy relies on the radical dissociating with negligible energetic barrier beyond the endoergicity.

Further studies into the photodissociation pathways of 2-bromo-2-nitropropane and the dissociation channels of the 2-nitro-2-propyl radical intermediate.

These experiments investigate the decomposition mechanisms of geminal dinitro energetic materials by photolytically generating two key intermediates: 2-nitropropene and 2-nitro-2-propyl radicals. To characterize the unimolecular dissociation of each intermediate, we form them under collision-free conditions using the photodissociation of 2-bromo-2-nitropropane; the intermediates are formed at high internal energies and undergo a multitude of subsequent unimolecular dissociation events investigated herein. Complementing our prior work on this system, the new data obtained with a crossed-laser molecular beam scattering apparatus with VUV photoionization detection at Taiwan's National Synchrotron Radiation Research Center (NSRRC) and new velocity map imaging data better characterize two of the four primary 193 nm photodissociation channels.

Imaging and scattering studies of the unimolecular dissociation of the BrCH2CH2O radical from BrCH2CH2ONO photolysis at 351 nm.

We report a study of the unimolecular dissociation of BrCH2CH2O radicals produced from the photodissociation of BrCH2CH2ONO at 351/355 nm. Using both a crossed laser-molecular beam scattering apparatus with electron bombardment detection and a velocity map imaging apparatus with tunable VUV photoionization detection, we investigate the initial photodissociation channels of the BrCH2CH2ONO precursor and the subsequent dissociation of the vibrationally excited BrCH2CH2O radicals. The only photodissociation channel of the precursor we detected upon photodissociation at 351 nm was O-NO bond fission.

Elucidating the decomposition mechanism of energetic materials with geminal dinitro groups using 2-bromo-2-nitropropane photodissociation.

These experiments photolytically generate two key intermediates in the decomposition mechanisms of energetic materials with nitro substituents, 2-nitropropene, and 2-nitro-2-propyl radicals. These intermediates are produced at high internal energies and access a number of competing unimolecular dissociation channels investigated herein. We use a combination of crossed laser-molecular beam scattering and velocity map imaging to study the photodissociation of 2-bromo-2-nitropropane at 193 nm and the subsequent unimolecular dissociation of the intermediates above.

Characterizing the rovibrational distribution of CD2CD2OH radicals produced via the photodissociation of 2-bromoethanol-d4.

This work characterizes the internal energy distribution of the CD(2)CD(2)OH radical formed via photodissociation of 2-bromoethanol-d(4). The CD(2)CD(2)OH radical is the first radical adduct in the addition of the hydroxyl radical to C(2)D(4) and the product branching of the OH + C(2)D(4) reaction is dependent on the total internal energy of this adduct and how that energy is partitioned between rotation and vibration. Using a combination of a velocity map imaging apparatus and a crossed laser-molecular beam scattering apparatus, we photodissociate the BrCD(2)CD(2)OH precursor at 193 nm and measure the velocity distributions of the Br atoms, resolving the Br((2)P(1/2)) and Br((2)P(3/2)) states with [2 + 1] resonance enhanced multiphoton ionization (REMPI) on the imaging apparatus.