Hydrogen tunnelling influences the isomerisation of some small radicals of interstellar importance: a theoretical investigation

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dc.contributor.authorWang, T.
dc.contributor.authorBowie, J.
dc.date.issued2012
dc.description.abstractHydrogen atom isomerisations within five radical systems (i.e., CH3˙NH/CH2NH; CH3O/CH2OH; CH2SH/CH3S; CH3CO2/CH2CO2H; and HOCH2CH2O/HO˙CHCH2OH) have been studied via quantum-mechanical hydrogen tunnelling through reaction barriers. The reaction rates including hydrogen tunnelling effects have been calculated for these gas phase reactions at temperatures from 300 K to 0 K using Wenzel–Kramers–Brillouin (WKB) and Eckart methods. The Eckart method has been found to be unsatisfactory for the last two systems listed above, because it significantly underestimates the width of the reaction barriers for the interconversions. The calculations at all-electron CCSD(T)/CBS level of theory indicate that the barriers for all reactions (forward and reverse) are greater than 100 kJ mol−1, meaning that the chemical reactivity of the reactants is limited in the absence of hydrogen tunnelling. Hydrogen tunnelling, in some cases, enhance rates of reaction by more than 100 orders of magnitude at low temperature, and around 2 orders of magnitude at room temperature, compared to results obtained from canonical variational transition state theory. Tunnelling corrected reaction rates suggest that some of these isomerisation reactions may occur in interstellar media.
dc.description.statementofresponsibilityTianfang Wang and John H. Bowie
dc.identifier.citationOrganic and Biomolecular Chemistry, 2012; 10(16):3219-3228
dc.identifier.doi10.1039/c2ob07102a
dc.identifier.issn1477-0520
dc.identifier.issn1477-0539
dc.identifier.urihttp://hdl.handle.net/2440/73761
dc.language.isoen
dc.publisherRoyal Soc Chemistry
dc.relation.grantARC
dc.relation.grantARC
dc.rightsThis journal is © The Royal Society of Chemistry 2012
dc.source.urihttps://doi.org/10.1039/c2ob07102a
dc.subjectHydrogen
dc.subjectFree Radicals
dc.subjectExtraterrestrial Environment
dc.subjectIsomerism
dc.subjectElectrons
dc.subjectQuantum Theory
dc.titleHydrogen tunnelling influences the isomerisation of some small radicals of interstellar importance: a theoretical investigation
dc.typeJournal article
pubs.publication-statusPublished

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