Chemical Physics Letters, Vol.443, No.4-6, 227-231, 2007
IR spectra of phenol(+)-Kr-n cluster cations (n=1,2): Evidence for photoionization-induced pi -> H isomerization
Phenol(+)-Kr cations (PhOH+-Kr) generated by photoionization (REMPI) of the neutral complex and in an electron ionization (El) source were assayed by their infrared (IR) spectra in the OH stretch (nu(OH)) range. Two isomers are identified in the EI-IR spectrum by their Delta nu(OH) complexation shifts: the more stable H-bound global minimum (Delta nu(OH) = -123 cm(-1)) and the less stable pi-bound local minimum (Delta nu(OH) = +1 cm(-1)). The REMPI-IR spectrum reveals VOH absorptions assigned to cold pi-bound complexes and hot H-bound dimers. The latter are generated via it H isomerization after the ionization of neutral pi-bound dimers. EI-IR spectra are also presented for PhOH+-Kr-2. Quantum chemical calculations support the interpretation of the spectroscopic data. (C) 2007 Elsevier B.V. All rights reserved.