It is shown that symmetrized wave functions of tetrahedral molecules can be used to derive the calculational formulae for the coefficients of broadening of the spectral lines corresponding to the transitions from the energy levels with symmetry of the A1 , A2 , and E types. The formulae for the wave–breaking function taking into account the octupole–octupole, octupole–quadrupole, and dispersion interactions are derived in the Anderson–Tsao–Curnutte approximation. For A and E–type transitions the coefficients of pressure broadening of spectral lines of the n4 band of methane by air and nitrogen have been calculated. Comparison between experimental and computational data shows their good qualitative agreement.