Vibrational coupling between proton and flanking group motions in the ionic hydrogen bond (IHB) of (CH3OH)(2)H+ were studied by solving reduced-clithensiorr vibrational.Schrodinger equations. Potential,energy and dipole, surfaces along a few key normal modes were constructed with high-level ab initio methods. It was found that the IHB stretch parallel to O-O axis strongly couples with the out of phase C-O stretch and out-of-phase in-plane CH3 rock with COH deformation. Such strong quantum coupling leads to a complex triplet at 850-1100 cm(-1) region. Furthermore; we have investigated the possible active role of torsional motion in intenSity redistribution.