Water adsorbed on titania/silica (TS) surfaces has been studied by die
lectric spectroscopy (DS) in the 3-10 MHz frequency range at T = 120-3
00 K, thermally stimulated depolarization (TSD) at the same temperatur
es, H-1 NMR, and quantum chemical methods. The TSD spectra of TS have
only one relaxation maximum after sample heating at 400 K. The activat
ion energies of depolarization (TSD) and polarization (DS) decrease at
TiO2 content increasing in TS. According to the TSD, DS, and H-1 NMR
data, water adsorbed on the TS surfaces essentially in the interface-r
egion forms more weakly bound clusters than on the silica surfaces. Si
mulation of vibrational-rotational relaxation of the water molecules a
ttached to the TS surfaces shows that the activation energy of rotatio
n is a maximum for the molecules having donor-acceptor bonds, Me<--OH2
(Me = Si, Ti), in the complexes HO-Me<--OH2 + mH(2)O and it is minimu
m for one water molecule linked to the Ti-O(H)-Si bridge through a hyd
rogen bond.