Matrix isolation and quantum chemical studies on the H2O2–SO2 complex

Abstract

Complexation and photochemical reactions of hydrogen peroxide and sulfur dioxide have been studied in solid Ar, Kr and Xe. Complexes between H₂O₂ and SO₂ are characterized using Fourier transform infrared spectroscopy and ab initio calculations. In solid Ar, the H₂O₂–SO₂ complex absorptions are found at wavenumbers of 3572.8, 3518.7, 3511.2, 3504.3, 1340.3, 1280.2 and 1149.9 cm⁻¹. In Kr and Xe matrices, the bonded OH stretching frequencies deviate from the values in Ar, and we propose that the matrix surrounding influences the structure of the H₂O₂–SO₂ complex. UV photolysis of the H₂O₂–SO₂ was also studied in solid Ar, Kr and Xe. This photolysis produces mainly a complex between sulfur trioxide and water via in-cage reaction.