The a1Δ g→ X3Σ −g magnetic dipole transition of S 2

Abstract

Emission spectra of the 0–0 band of the a 1Δ g → X 3Σ − g magnetic dipole transition of S 2 have been observed in the near-infrared spectral region near 4400 cm −1. The S 2 molecules were generated in a fast-flow system by passing S x or S 2Cl 2 vapor in Ar carrier gas through a microwave discharge and were excited by electronic-to-electronic energy transfer from metastable singlet oxygen O 2( a 1Δ g ). Medium-resolution spectra of the b 1Σ + g → X 3Σ − g and a 1Δ g → X 3Σ − g transitions of S 2 were measured with a Fourier-transform spectrometer. By comparing the bandshape of the 0–0 band of the a→ X system with a computer simulation calculated with literature data of the rotational constants of the X and a states, the origin of the 0–0 band was determined to be ν 0=4394.25±0.2 cm −1.