The b1Σ +( b0 +) → X3Σ −( X10 +, X21) and a1Δ( a2) → X21 transitions of AsBr

Abstract

Emission spectra of the b 1Σ +( b0 +) → X 3Σ −( X 10 +, X 21) and a 1Δ( a2) → X 21 transitions of AsBr have been measured in the near-infrared spectral region with a Fourier-transform spectrometer. The arsenic bromide radicals were generated in fast-flow systems by reaction of arsenic vapor (As x) with bromine and were excited by microwave-discharged oxygen. The most prominent features in the spectrum are the Δ v = +1,0,−1, and −2 band sequences of the b 1Σ +( b0 +) → X 3Σ −( X 10 +) transition in the range 11 700–12 700 cm −1. With lower intensities, the Δ v = 0 and −1 sequences of the b 1Σ +( b0 +) → X 3Σ −( X 21) sub-system show up in the same range. Further to the red, between 6000 and 6700 cm −1, the Δ v = 0, +1, and −1 sequences of the hitherto unknown a 1Δ( a2) → X 21 transition are observed. Analyses of medium- and high-resolution spectra have yielded improved molecular constants for the X 10 +, X 21, and b0 + states and first values of the electronic energy and the vibrational constants of the a2 state.