H-Bonded CH3SO/H2SO4/H2O Complexes: A Quantum Chemical Study.

Area of Science:

• Atmospheric Chemistry
• Computational Chemistry
• Spectroscopy

Background:

• New particle formation is a key atmospheric process.
• Understanding molecular interactions is vital for atmospheric modeling.
• Methyl sulfinyl radical, sulfuric acid, and water are relevant atmospheric species.

Purpose of the Study:

• To investigate the structural, electronic, and spectroscopic properties of complexes formed by methyl sulfinyl radical (CH(3)SO), sulfuric acid (H(2)SO(4)), and water (H(2)O).
• To characterize hydrogen bond interactions within these complexes.
• To assess the stability and potential atmospheric relevance of these molecular complexes.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Ab initio quantum chemistry methods (CBS-QB3 level).
• Analysis of binding energies, electronic spectra, and photochemical properties.

Main Results:

• Calculations predicted significant binding energies for CH(3)SO-H(2)SO(4) and its hydrated complexes, with the most stable complex (CH(3)SO-H(2)SO(4)-2H(2)O) exhibiting a binding energy of 28.8 kcal mol-1.
• The high stabilization of these complexes suggests a substantial role in atmospheric new particle formation.
• Electronic and photochemical spectral features were examined, indicating potential for photolysis in sunlight.

Conclusions:

• The studied complexes are thermodynamically stable and likely influence atmospheric new particle formation.
• Infrared spectroscopy is proposed as a valuable technique for detecting these complexes in laboratory and atmospheric settings.
• The electronic and photochemical properties suggest that hydrated complexes can undergo photolysis, impacting atmospheric chemistry.