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Faculty of Science - Papers (Archive)

2011

Formation

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Communication: New Insight Into The Barrier Governing Co2 Formation From Oh + Co, Christopher J. Johnson, Berwyck L. Poad, Ben B. Shen, Robert E. Continetti Jan 2011

Communication: New Insight Into The Barrier Governing Co2 Formation From Oh + Co, Christopher J. Johnson, Berwyck L. Poad, Ben B. Shen, Robert E. Continetti

Faculty of Science - Papers (Archive)

Despite its relative simplicity, the role of tunneling in the reaction OH + CO → H + CO(2) has eluded the quantitative predictive powers of theoretical reaction dynamics. In this study a one-dimensional effective barrier to the formation of H + CO(2) from the HOCO intermediate is directly extracted from dissociative photodetachment experiments on HOCO and DOCO. Comparison of this barrier to a computed minimum-energy barrier shows that tunneling deviates significantly from the calculated minimum-energy pathway, predicting product internal energy distributions that match those found in the experiment and tunneling lifetimes short enough to contribute significantly to the overall reaction. …


Alunite Formation Within Silica Stalactites From The Sydney Region, South-Eastern Australia, Robert A. Wray Jan 2011

Alunite Formation Within Silica Stalactites From The Sydney Region, South-Eastern Australia, Robert A. Wray

Faculty of Science - Papers (Archive)

"This paper presents X-ray diffraction and SEM evidence for the formation of alunite, and possibly small quantities of natroalunite, within opal-A stalactites formed on quartz sandstone near Sydney in south-eastern, Australia. Alunite has been reported as a speleogenetic mineral from sediments within a number of caves around the world, but this is believed to be the first report of speleothemic alunite in opaline silica speleothems. Individual alunite crystals have not been visually identified, but SEM X-ray element mapping suggests the alunite has formed amongst kaolinite clay. Sedimentary alunite and natroalunite formation is usually associated with the reaction of sulphuric acid …