The origin of 1560 cm-1 band in experimental IR spectra of water adsorbed on TiO2 surface: Ab initio assessment

We present DFT study on vibrational spectrum of water layer on a surface of TiO2 which is modeled via Ti8O16 nanocluster. In contrast to v(2) mode's frequency of liquid water (1645 cm(-1)) for the water layer theory predicts considerably lower v2 frequency (1570 cm(-1)) which matches experimentally observed shoulder in IR spectrum (1560 cm(-1)). We demonstrate that the calculated v(2) frequencies depend linearly on a distance between adsorbed water molecules and a surface of Ti8O16 nanoclusterl We also show that hydrogen bonding strongly affects v(1) vibrational frequencies but leaves v(2) and v(3) ones almost intact. (C) 2016 Elsevier B.V. All rights reserved.