Absolute photoabsorption cross sections at room temperature are reported for Cl-2 (190-500 nm), Br-2 (190-600 nm), and BrCl (190-560 nm). In addition, cross sectional data for BrCl were deconvoluted using a semi-logarithmic gaussian distribution function into a UV band centered at 228.3 nm, a C (1) Pi(1) band centered at 376.4 nm, a B (3) Pi(0)(+) band centered at 454.9 nm, and an A (3) Pi(1) band centered at 533.1 nm. The BrCl band maximum at approximately 228 nm of 6.0 x 10(-20) cm(2) molecule(-1) was assigned to a transition from the X(1) Sigma(o)(+) ground state to a repulsive 0(+) electronic state by analogy with similar UV bands present in ICl and IBr. Finally, an absorbance maximum was also detected for Br-2 at 227 nm of 0.96 x 10(-20) cm(2) molecule(-1).
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY