Many density functional theory approaches fail to give reliable large hydrocarbon isomer energy differences.
[structure: see text] Several DFT methods were found to be unreliable for computing hydrocarbon isomer energy differences. The errors grow with system size up to 20 kcal mol(-1) for the relative energies of the (CH)12 isomers; octahedrane is the most stable (CH)12 hydrocarbon. While DFT geometries generally are good, problems arise for structures with single bonds only, especially for small rings. We recommend the use of higher level, non-DFT energy single points computed at DFT-optimized structures.
Schreiner
Peter R
PR
Institute of Organic Chemistry, Justus-Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany. prs@org.chemie.uni-giessen.de
Fokin
Andrey A
AA
Pascal
Robert A
RA
de Meijere
Armin
A