title: Jet-cooled spectroscopy of paracetamol.
abstract: We have measured the resonant 2-photon ionization spectrum of jet-cooled p-acetaminophenol (paracetamol) between 33,400 cm(-1) and 45,500 cm(-1), and analysed the results in the light of theoretical calculations of the ground-state geometry and vibrational frequencies. The experimental spectrum consists of a large number of clearly resolved vibronic transitions, and some evidence of rotational structure. It is dominated by a repeated progression with a regular spacing of 33 cm(-1) (believed to be the methyl-torsion mode) in combination with normal modes of vibration which involve the stretching of the C-C bonds in the phenyl ring and bending of the C-N-C bond in the amide group. The intensity pattern of the progressions in the methyl torsion is consistent with structural changes between the minimum-energy geometries in the ground and excited states.
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Beames
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Hudson
mesh_terms: D000082:Acetaminophen / Q000737:chemistry*; D003080:Cold Temperature; D017785:Photons; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000082:Acetaminophen