Quantum calculations of highly excited vibrational spectrum of sulfur dioxide. III. Emission spectra from the (C)over-tilde(1) B-2 state

We report quantum mechanical calculations of the (X) over tilde <--(C) over tilde emission spectra of SO2 at the red wing of the (C) over tilde absorp tion band. The near equilibrium potential energy surface of the (C) over ti lde B-1(2) state is deduced by fitting experimental vibrational frequencies using an exact quantum mechanical Hamiltonian. Low-lying vibrational eigen energies on this double minimum potential agree well with experimental freq uencies and the corresponding eigenstates show some interesting features. B oth spectral positions and intensities of the (X) over tilde <--(C) over ti lde transitions are obtained up to 16 000 cm(-1) using a Chebyshev based sp ectral method, which does not explicitly construct vibrational eigenfunctio ns in the (X) over tilde state. The emission spectra are in reasonably good agreement with experimental measurements. (C) 1999 American Institute of P hysics. [S0021-9606(99)01741-9].