IR spectrum of molecular complexes of sulfuric acid with N2 and NO trapped in solid argon

Abstract

The IR spectra of vapours above neat sulfuric acid trapped, mixed with varying amounts of N₂ and NO gases in argon matrices are reported. Absorptions due to 1:1 (N₂)·(H₂O), (N₂)·(H₂SO₄), (NO)·(H₂O), (NO)·(H₂SO₄) and (N₂O₂)·(H₂SO₄) dimeric complexes were identified in all relevant spectral regions. The interactions of nitrogen and nitrogen oxides with SO₃ do not indicate complex formation. A T-shaped attachment of N₂ to H₂SO₄, and an O-end interaction of the nitrogen oxide monomer and dimer with the OH groups of H₂SO₄ is suggested. The formation of the complex species is by surface diffusion during deposition and not a result of vapour phase equilibria.