Continuum and discrete pulsed cavity ring down laser absorption spectra of Br 2 vapor

Abstract

The absorption cross-sections at room temperature are reported for the first time, of Br 2 vapor in overlapping bound–free and bound–bound transition of A 3Π 1u ← XΣ g +, X 1Π 1u ← X 1Σ g + and B 3Π 0u ← X 1Σ g +, using cavity ring down spectroscopy (CRDS) technique. We reported here, the A 3Π 1u ← X 1Σ g +, transition is included along with the two stronger X 1Π 1u ← X 1Σ g + and B 3Π 0u ← X 1Σ g transitions of Br 2. 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 A 3Π 1u ← X 1Σ g +, 1Π 1u ← X 1Σ g +, and B 3Π 0u ← X 1Σ g + transitions using CRDS method to use quantum yield of Br *( 2P 1/2). We obtained absorption cross-section order 10 −19 cm 2 and detection 10 13 molecule cm −3 (1 mTorr) of Br 2. The absorption cross-sections are increasing with increasing excitation energy in the wavelength region 510–535 nm.