A B3LYP and mPW1PW91/6-31++G(d.p) study of phenol-benzene(+) radical cation was performed, revealing an existence of T-shaped O-H...pi hydrogen bonded minima at both PES-s. with center-of-mass separation of 5.087 Angstrom (B3LYP) and 4.970 Angstrom (mPW1PW91) and the interplanar angle between monomeric units of 89.9degrees and 89.4degrees (at B3LYP and mPW1PW91 levels correspondingly). Calculated anharmonic O-H vibrational frequencies on the basis of one-dimensional DFT vibrational potentials reproduce excellently the experimentally measured v(OH) frequency shift upon this interaction. According to CFP-like calculations, most of the interaction energy (47.09 and 49,64 kJ mol(-1) at B3LYP and mPW1PW91 levels correspondingly) is of electrostatic origin. (C) 2002 Elsevier Science B.V. All rights reserved.