Photoisomerization of acetone via Rydberg excitation

Acetone photochemistry upon excitation by vacuum ultraviolet (VUV) radiation of photon energy 7.75 eV has been investigated under a cryogenic condition of an argon matrix (8 K) and also by shining the molecule seeded in an effusive beam of argon prior to matrix deposition on a pre-cooled KBr window, where the photo-products get trapped in the argon matrix. Product analysis by infrared spectroscopy reveals appearance of the characteristic enolic O-H stretching fundamental at 3622 cm -1 and other bands in the infrared fingerprint region, including C=C stretching only in the gas phase. The findings reveal the opening of a new isomerization reaction channel of acetone over the popular Norrish type-I α-CC bond cleavage upon VUV excitation to high-lying Rydberg states. Graphical abstract: SYNOPSIS Photochemical transformation of acetone upon excitation by vacuum ultraviolet radiation of photon energy 7.75 eV is reported under a cryogenic condition of an argon matrix (8 K). Infrared spectroscopic analysis of the products reveals that acetone isomerizes to the enolic form, 1-propene-2-ol, upon excitation to the high-lying Rydberg states.