Definitive heat of formation of methylenimine, CH2=NH, and of methylenimmonium ion, CH2NH2+, by means of W2 theory

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dc.creatorde Oliveira, Glenisson
dc.creatorMartin, Jan M. L.
dc.creatorSilwal, Indira K. C.
dc.creatorLiebman, Joel F.
dc.date2001-01-10
dc.date.accessioned2026-07-07T05:45:18Z
dc.date.available2026-07-07T05:45:18Z
dc.descriptionA long-standing controversy concerning the heat of formation of methylenimine has been addressed by means of the W2 (Weizmann-2) ab initio thermochemical approach. Our best calculated values, DeltaHf298(CH2NH)=21.1+/-0.5 kcal/mol and DeltaHf298(CH2NH2+)=179.4+/-0.5 kcal/mol, are in good agreement with the most recent measurements but carry a much smaller uncertainty. As a by-product, we obtain the first-ever accurate anharmonic force field for methylenimine: upon consideration of the appropriate resonances, the experimental gas-phase band origins are all reproduced to better than 10 cm-1. Consideration of the difference between a fully anharmonic zero-point vibrational energy and B3LYP/cc-pVTZ harmonic frequencies scaled by 0.985 suggests that the calculation of anharmonic zero-point vibrational energies can generally be dispensed with, even in benchmark work, for rigid molecules.
dc.descriptionRevTeX, 20 pages. J. Comput. Chem., in press JCC10266/F-204 (Paul von Ragué Schleyer festschrift) Supplementary material: complete CCSD(T)/cc-pVTZ quartic force field available at http://theochem.weizmann.ac.il/web/papers/ch2nh.html
dc.identifierhttps://arxiv.org/abs/physics/0101051
dc.identifierhttp://arxiv.org/abs/physics/0101051
dc.identifierJournal of Computational Chemistry 22, 1297-1305 (2001)
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/83947
dc.subjectChemical Physics
dc.subjectComputational Physics
dc.titleDefinitive heat of formation of methylenimine, CH2=NH, and of methylenimmonium ion, CH2NH2+, by means of W2 theory
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