Infrared spectroscopy of the phenol-N-2 cluster in S-0 and D-0: Direct evidence of the in-plane structure of the cluster

The OH stretching vibration of jet-cooled phenol-N-2 in the neural and cati onic ground states was observed by using infrared-ultraviolet double resona nce spectroscopy and infrared photodissociation spectroscopy, respectively. The OH vibration showed a small but significant low-frequency shift of 5 c m(-1) upon the cluster formation in the neutral, while the shift drasticall y increased up to 159 cm(-1) in the cation. These results represent the dir ect evidence of the in-plane cluster structure, in which phenolic OH is hyd rogen bonded to N-2, as was proposed in the zero kinetic energy photoelectr on study [S. R. Haines et al., J. Chem. Phys. 109, 9244 (1998)]. (C) 1999 A merican Institute of Physics. [S0021-9606(99)02023-1].