Document Detail


Enthalpy of the gas-phase CO2 + Mg reaction from ab initio total energies.
MedLine Citation:
PMID:  12132886     Owner:  NLM     Status:  PubMed-not-MEDLINE    
Abstract/OtherAbstract:
Various highly accurate ab initio composite methods of Gaussian-n (G1, G2, G3), their variations (G2(MP2), G3(MP2), G3//B3LYP, G3(MP2)//B3LYP), and complete basis set (CBS-Q, CBS-Q//B3LYP) series of models were applied to compute reaction enthalpies of the ground-state reaction of CO2 with Mg. All model chemistries predict highly endothermic reactions, with DeltaH(298) = 63.6-69.7 kcal x mol(-1). The difference between the calculated reaction enthalpies and the experimental value, evaluated with recommended experimental standard enthalpies of formation for products and reactants, is more than 20 kcal x mol(-1) for all methods. This difference originates in the incorrect experimental enthalpy of formation of gaseous MgO given in thermochemical databases. When the theoretical formation enthalpy for MgO calculated by a particular method is used, the deviation is reduced to 1.3 kcal x mol(-1). The performance of the methodologies used to calculate the heat of this particular reaction and the enthalpy of formation of MgO are discussed.
Authors:
Antonija Lesar; Sasa Prebil; Milan Hodoscek
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Journal of chemical information and computer sciences     Volume:  42     ISSN:  0095-2338     ISO Abbreviation:  J Chem Inf Comput Sci     Publication Date:    2002 Jul-Aug
Date Detail:
Created Date:  2002-07-22     Completed Date:  2002-09-03     Revised Date:  2003-11-03    
Medline Journal Info:
Nlm Unique ID:  7505012     Medline TA:  J Chem Inf Comput Sci     Country:  United States    
Other Details:
Languages:  eng     Pagination:  853-7     Citation Subset:  -    
Affiliation:
Department of Physical and Organic Chemistry, Jozef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia. antonija.lesar@ijs.si
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