R2PI Study of Intermolecular Hydrogen Bond in Solvent-Free Chiral Complexes

One- and two-color, mass selected R2PI spectra of the S1S0 transitions in the bare (+)-(R)-1-phenyl-1-ethanol (ER) and its complexes with different solvent mols. (solv) (-)-(R)-2-butanol (BR) or (+)-(S)-2-butanol (BS) and (-)-(R)-2-butylamine (AR) or (+)-(S)-2-butylamine (AS), have been recorded after a supersonic mol. beam expansion. The one-color R2PI excitation spectra of the diastereomeric complexes are characterized by significant shifts of their band origin relative to that of bare ER. The extent and the direction of these spectral shifts are found to depend on the structure and the configuration of solv and are attributed to different short-range interactions in the ground and excited states of the complexes. In analogy with other diastereomeric complexes, the phenomenol. binding energy of the homochiral cluster is found to be greater than that of the heterochiral one.