NEW VIBRATIONAL ANALYSIS OF THE B-1(2)((1)DELTA(U)) STATE OF CS2

Sub-Doppler excitation spectra of CS2 in the spectral range of 29 600 - 32 800 cm(-1) (V-system) are measured with a frequency doubled conti nuous wave (cw) single-mode dye laser. The ultraviolet (UV) radiation is generated in an external enhancement cavity. The average output pow er is about 5 mW, which is sufficient to resolve weak rotational lines in the excitation spectra of hot bands from the (0,2(2),0) level of t he ground state. This increased the number of measured transitions wit h K >0 considerably. The low temperature achieved by adiabatic cooling of CS2 seeded in a supersonic argon beam simplifies the spectrum and allows an exact assignment of the rotational lines. Based on new ab in itio calculations, a revised electronic state and vibrational assignme nt of the bands were necessary and will be presented. From this vibrat ional analysis the geometry, the position of the barrier to Linearity, and the rotational constants of the CS2 molecule in the V B-1(2)((1)D elta(u)) state have been determined, revising former results. A statis tical analysis of the positions of all measured bands shows a pure Poi ssonian nearest level distribution indicating no correlation between n eighboring vibrational levels nor long-range interactions. (C) 1998 Am erican Institute of Physics.