EMISSION-SPECTROSCOPY OF JET-COOLED CS2 UPON EXCITATION OF THE (1)SIGMA(-]B-1(2)((1)SIGMA(+)(U)) TRANSITION IN THE 48,500-51,000 CM(-1) REGION()(G))

The jet-cooled emission spectroscopy of gaseous carbon disulfide (CS2) was performed in the 48500-51000 cm(-1) region in order to investigat e changes in the early time dynamics of CS2 in the predissociative B-1 (2) ((1)Sigma(u)(+)) state. The spectra show emission into progression s of both the symmetric stretching (v(1)) and bending (v(2)) motions a nd combinations bands of these two motions. Analysis shows that the co ntribution of symmetric stretching and bending motion varies over the range of excitation wavelengths and the progression of v(2) decreases in intensity relative to the progression in v(1) as one scans through the energetic region near the barrier to linearity of this bent excite d state molecule. We estimate the barrier height to be approximately 3 400 cm(-1) above the zero-point level of the B-1(2) ((1)Sigma(u)(+)) s tate. (C) 1998 American Institute of Physics. [S0021-9606(98)00542-X].