Continuum and discrete pulsed cavity ring down laser absorption spectra of Br2 vapor

The absorption cross-sections at room temperature are reported for the first time, of Br2 vapor in overlapping bound–free and bound–bound transition of A3Π1u ← XΣg+, X1Π1u ← X1Σg+ and B3Π0u ← X1Σg+, using cavity ring down spectroscopy (CRDS) technique. We reported here, the A3Π1u ← X1Σg+, transition is included along with the two stronger X1Π1u ← X1Σg+ and B3Π0u ← X1Σg transitions of Br2. We obtained discrete absorption cross-section in the rotational structure, the continuum absorption cross-sections, and were also able to measure the absorption cross-section in separate contribution of A3Π1u ← X1Σg+, 1Π1u ← X1Σg+, and B3Π0u ← X1Σg+ transitions using CRDS method to use quantum yield of Br*(2P1/2). We obtained absorption cross-section order 10−19 cm2 and detection 1013 molecule cm−3 (1 mTorr) of Br2. The absorption cross-sections are increasing with increasing excitation energy in the wavelength region 510–535 nm.