Branching ratio in photodissociation of 1-bromo-3-chlorobenzene cation.

A new and convenient calculation method based on Rice-Ramsperger-Kassel-Marcus (RRKM) theory assuming an extremely loose transition state (LTS) has been attempted to predict the branching ratio in photodissociation. This method enables estimation of the branching ratios without detailed structural information on the transition state which is indispensable in conventional RRKM calculations. To evaluate our simple method through comparison to the experimental results, photodissociation of 1-bromo-3-chlorobenzene cation (3BCB) was chosen as a model unimolecular reaction system which has two distinct photodissociation channels in ultraviolet region: 3BCB → Br-dissociated daughter ion (ClBz) + Br and 3BCB → Cl-dissociated daughter ion (BrBz) + Cl.

Structures and infrared photodissociation of [(aniline)-(methanol)-(water)].

The structures of [(aniline)-(methanol)-(water)] were investigated by infrared spectroscopy coupled with linear tandem mass spectrometry. We suggest the most stable structure of [(aniline)-(methanol)-(water)] through infrared photodissociation spectra supported by the density functional theory calculations at the level of ωB97X-D/cc-pVQZ. Methanol and one water molecule formed hydrogen bonding with the amino group of aniline, while the other water formed hydrogen bonding with methanol.