Abstract
The geometrical parameters, vibrational frequencies, and dissociation energies for (H2O) n and C6H6(H2O) n (n = 1–7) clusters have been investigated using density functional theory (DFT) with various basis sets. The highest levels of theory employed are B3LYP/aug-cc-pVTZ for optimization and MP2/aug-cc-pVTZ//B3LYP/aug-cc-pVTZ for binding energy. The harmonic vibrational frequencies and IR intensities are also determined at the various levels of theory to confirm whether the hydrogen-bonded structure of water complex (W n , n = 1–7) is affected by the presence of benzene. The effect of benzene on the OH stretch modes of benzene–water complex (BW n , n = 1–7) is observed in the π-hydrogen bonded OH stretch. For each of the BW n clusters the intensity of this mode is increased significantly due to charge transfer/polarization interactions and the frequency shifts from W n to BW n are in the range of 40–60 cm−1. The calculations give the binding energies of 2.58, 4.20, 3.27, 3.00, 3.42, 4.14, and 5.49 kcal/mol for BW1–BW7, respectively after ZPVE and 50%-BSSE corrections.
Acknowledgements
This paper was supported by Hannam University in 2009 and also by the Korean Council for Education, grant funded by Korean Government (MOEHRD) for 2008 Domestic Faculty Exchange.