@article{MAKHILLRJAS2008358941,
    title = {Thermochemical Analyses of Sulphur Compounds: Implications for Atmospheric Sulphur Oxidation},
    journal = {Research Journal of Applied Sciences},
    volume = {3},
    number = {5},
    pages = {393-406},
    year = {2008},
    issn = {1815-932x},
    doi = {rjasci.2008.393.406},
    url = {https://makhillpublications.co/view-article.php?issn=1815-932x&doi=rjasci.2008.393.406},
    author = {Anselm I. Igbafe,Linda L. Jewell and},
    keywords = {Thermochemistry (analysis),energies,sulphur,atmosphere,reactions},
    abstract = {A theoretical study of the thermochemical properties of some common sulphur species present in the atmosphere including the intermediates and end-product of their transformation is reported here. These properties were obtained from the approximation of the Schr&ouml;dinger equation<SUP> </SUP>as applied in Gaussian 03 (G03) model chemistry package. Analyses of the chemical reaction equilibrium for a variety of atmospheric sulphur transformations were investigated with a view to establish the thermodynamically favourable reaction pathways over ambient tropospheric temperature range of between -50 and +50°C. Seven high-energy accuracy model chemistries methods integrated in G03 comprising several <I>ab initio </I>methods and density functional theory (DFT) methods were applied for the computation. The computational methods were tested with a number of basis sets to yield values approximating those of experimental observations. Of all chosen methods, the complete basis set (CBS-Q) method was observed to closely approximate the experimentally determined thermodynamic enthalpies and Gibbs free energies of reactions. The CBS-Q method produced a mean absolute deviation (MAD) of 1.08% as against experimental data. Of the gas-phase and aqueous-phase reactions about 80 and 59.6%, respectively will most likely attain equilibrium over a temperature range of between -100 and +100°C. Whilst about 15 and 23.4% will not like reach equilibrium the specified temperature range and about 5 and 17% may attain equilibrium at higher temperatures above 20°C. The 4 most important oxidising species involved in the gas-phase reactions of atmospheric SO<SUB>2 </SUB>have been characterized in an order of increasing oxidant’s potentials in the form CH<SUB>3</SUB>O<SUB>2</SUB>* &lt; HO<SUB>2</SUB>* &lt; OH* &lt; O*.}
    }