A theoretical investigation of HSO/HOS and their positive ions
- Department of Chemistry, University of Missouri-Columbia, Columbia, MO (USA) Department of Physics, University of Missouri-Columbia, Columbia, MO (USA)
The formation and eventual fate of sulfur-containing aerosols play a central role in global pollution. An understanding of the oxidation paths for sulfur species and of the formation and stability of radical and ionic intermediates is required for optimum control of acid deposition. To gain insight into these processes {ital ab} {ital initio} calculations were performed for ground and first excited electronic states of the isomers HSO/HOS and for the ground and first two excited states for their positive ions, HSO{sup +}/HOS{sup +}. A variety of basis sets were used for calculations at the self-consistent field (SCF) level. (Full details available in supplementary material for this article.) These calculations included full optimization of the geometry and examination of the potential surface for transition states. Post Hartree--Fock calculations were performed and included Moller--Plesset calculations through fourth order with quadruple excitations as well as configuration interaction including all double excitations. The effect of geometry optimization at the MP4 level and the effect of freezing the core orbitals in the calculations were examined. Five transition states for the isomerization of HSO to HOS were located for the ground and excited electronic states of the neutral and ion systems. For all transition states in both systems, the geometry resembles an isosceles triangle. The barriers to rearrangement are quite high, ranging from {similar to}20 to {similar to}60 kcal/mol depending on the state. Two of the barriers were approximately symmetric while three were asymmetric with a lower barrier for HSO to HOS isomerization.
- OSTI ID:
- 6776873
- Journal Information:
- Journal of Chemical Physics; (USA), Vol. 92:11; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SULFUR COMPOUNDS
ELECTRONIC STRUCTURE
ISOMERIZATION
ACID RAIN
AIR POLLUTION
ATMOSPHERIC CHEMISTRY
CATIONS
CONFIGURATION INTERACTION
CONFORMATIONAL CHANGES
HARTREE-FOCK METHOD
OXIDATION
POLLUTANTS
RADICALS
ATMOSPHERIC PRECIPITATIONS
CHARGED PARTICLES
CHEMICAL REACTIONS
CHEMISTRY
IONS
POLLUTION
RAIN
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)