In order to describe correctly the complicated nature of the nuclear motion in CH2OH a dynamic model of CH2OH was developed. The strong structural flexibility due to the out-of-plane motions and the appreciable anharmonicity along some in-plane vibrational modes were taken into consideration. The dynamic problem was done separately for the out-of-plane and in-plane vibrational modes in a basis set of harmonic oscillator eigenfunctions. Potential energy surfaces dependent on displacements of all nine internal coordinates from their equilibrium values in the planar structure of C-s symmetry were built using the energies of 1793 geometries of CH2OH. Computations were done with correlation-consistent polarized valence basis sets of triple zeta quality and at the second (MP2) and fourth (MP4) orders of many body perturbation theory, and by the coupled cluster singles and doubles method with perturbative treatment of triple excitations [CCSD(T)]. Infrared intensities of the lowest excitations were estimated by calculation of matrix elements of the dipole moment for the corresponding transitions. The vibrationally averaged values of the geometric parameters of CH2OH were computed. The results obtained were found to be in good agreement with available experimental data. (C) 2003 American Institute of Physics.