Hydrocarboxyl Radical as a Product of α-Alanine Ultraviolet Photolysis.

UV photodissociation of α-alanine was studied by parahydrogen matrix isolation infrared spectroscopy. The temporal behavior of Fourier transform infrared spectra revealed that UV irradiation at 213 nm yielded the HOCO radical as a direct photoproduct from the S excited state. The concentration of HOCO quickly approached a steady state due to secondary photodissociation of HOCO to produce CO + H or CO + OH.

VUV photochemistry and nuclear spin conversion of water and water-orthohydrogen complexes in parahydrogen crystals at 4 K.

Samples of H2O, HDO, and D2O were isolated in solid parahydrogen (pH2) matrices and irradiated by vacuum ultraviolet (VUV) radiation at 147 nm. Fourier-Transform Infrared (FTIR) spectra showed a clear depletion of D2O and an enrichment of both HDO and H2O by 147 nm irradiation. These irradiation-dependent changes are attributed to the production of OH and/or OD radicals through photodissociations of H2O, HDO, and D2O.