15min:

KADIR DIRI, THOMAS SOMMERFELD AND KENNETH D. JORDAN, Department of Chemistry and Center for Molecular and Materials Simulations, University of Pittsburgh, Pittsburgh, Pennsylvania 15260; JOSEPH R. ROSCIOLI AND MARK A. JOHNSON, Sterling Chemistry Laboratory, Yale University, P.O. Box 208107, New Haven, Connecticut 06520.

In this work we analyze the vibrational spectra of the (H₂O)₇^- cluster obtained by the Yale part of the team. The spectrum is interesting due to the appearance of different (H₂O)₇^- isomers depending on the number of attached Ar atoms. Parallel tempering Monte Carlo simulations performed using a one-electron model Hamiltonian with Drude oscillators to account for the polarization effects and dispersion interactions\footnoteWang, F.; Jordan, K. D. J. Chem. Phys. \textbf2001, 114 , 10717. are used to identify low-lying isomers of (H₂O)₇^-. Selected low-energy isomers are then characterized by means of the all-electron Becke3LYP, MP2, and CCSD(T) methods. We propose an assignment of the observed spectra based on comparison of calculated harmonic spectra and electron binding energies with the corresponding experimental values.