MULTIDIMENTIONAL NORMAL MODE CALCULATIONS FOR THE OH VIBRATIONAL SPECTRA OF (H2O)3+, (H2O)3+Ar, H+(H2O)3, AND H+(H2O)3Ar

Recent experimental observations of (H2O)3 , (H2O) + 3 Ar, H (H2O)3, and H(H2O)3Ar clusters in the region 14003800 cm−1show that the OH stretching vibration has distinct characteristics.abc Multidimensional normal mode calculations were carried out for OH stretching vibrations in the 1200-4000 cm−1photon energy range. The potential energy and dipole surfaces were evaluated by using first-principles methods. By comparing the calculated frequencies and intensities of OH stretching vibration with experimental spectra, we found that the assignment of OH strecthing of H3O moiety and free OH strectching vibration have resonable agreement with experimental data.