FINE-STRUCTURE-RESOLVED COLLISIONAL BROADENING IN THE SCHUMANN-RUNGE BANDS OF O-2

Collisional self-broadening and shift coefficients are presented for s elected fine-structure-resolved rotational lines from the B-3 Sigma(u) (-)<--X-3 Sigma(g)(-)(upsilon',1) bands of O-2. The coefficients were derived from high-resolution photoabsorption cross-sections measured u sing the tuneable, narrow-bandwidth, vacuum-ultraviolet radiation gene rated by the two-photon-resonant difference-frequency four-wave mixing of excimer-pumped dye-laser radiation in Xe. The results, obtained at room temperature and at pressures of less than 800 torr, are consiste nt with previous results derived from medium-resolution measurements o f the (upsilon',O) bands at much higher pressures. (C) 1997 Elsevier S cience Ltd.