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Accurate density‐functional calculations on large systems
Author(s) -
Dunlap Brett I.
Publication year - 1997
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/(sici)1097-461x(1997)64:2<193::aid-qua6>3.0.co;2-r
Subject(s) - fullerene , graphene , density functional theory , gaussian , work (physics) , statistical physics , chemistry , computational chemistry , physics , molecular physics , quantum mechanics
Efforts to compute accurate all‐electron density‐functionalenergies for large molecules and clusters using Gaussian basis sets arereviewed and their use in fullerene science described. The foundation ofthis effort, variational fitting, is described first. When discoveredexperimentally, C 60 was naturally assumed to be particularlystable, but local‐density‐functional calculations showed thatC 60 is quite unstable relative to the higher fullerenes andgraphene (a single sheet of graphite). In addition to raising questionsabout the relative abundance of the various fullerenes, this workconflicted with the then state‐of‐the‐art density‐functional calculationson crystalline graphene. Now high accuracy molecular and band structurecalculations are in fairly good agreement with each other and experiment.These calculations clearly demonstrate that each of the 12 pentagons, whichare necessary to close a fullerene, is best viewed as a rather high‐energy,more than 2 eV, defect in a graphene sheet. The effect of the heptagon, thesecond most common defect in fullerene materials, is described. Mostrecently, we have developed accurate, variational gradient‐corrected forcesfor use in geometry optimization of clusters and in molecular‐dynamicssimulations of friction. The gradient‐corrected optimized geometry ofC 60 is given. © 1997 John Wiley & Sons, Inc. Int JQuant Chem 64 : 193–203, 1997