Spectroscopic and ab initio studies of ionic hydrogen bonds: the O-H stretch vibration of SiOH+-X dimers (X = He, Ne, Ar, N-2)

Infrared photodissociation spectra of SiOH+-X dimers with X = He, Ne, Ar, a nd N-2 are analyzed in the vicinity of the O-H stretch (nu(1)) vibration of SiOH+. The observed complexation-induced red-shifts, Delta nu(1) = -8.4(3. 0), - 35.7(6), -217.42(1), and -517.1(5) cm(-1), are consistent with the Li near proton-bound global minimum structures predicted by ab initio calculat ions at the MP2 level of theory. Empirical relations between the magnitude of Delta nu(1) and the interaction strength of the ionic hydrogen bond are discussed. (C) 1999 Elsevier Science B.V. All rights reserved.