Vibrational spectra of water complexes with H2, N2, and CO

Ab initio calculations are carried out on the H2O•••N2, H2O•••H2, and H2O•••CO complexes. Infrared spectra of the complexes are investigated, with an emphasis on the effect of weak bonding on the frequencies and the infrared intensities of the monomers. Connections are explored between the computational results and the experimentally measured infrared spectra of ice surfaces covered by H2, N2, and CO adsorbate. Additional issues addressed include the influence of the counterpoise correction on the equilibrium geometry of the complexes, and the analysis of the different contributions ~exchange, dispersion, electrostatic! to the weak bonding, and to the frequency shifts. © 1995 American Institute of Physics.