Towards Fast and Reliable Quantum Chemical Modelling of Macromolecules
2006 (English)In: Lecture Notes in Computational Science and Engineering, ISSN 1439-7358, Vol. 49, 315-341 p.Article in journal (Refereed) Published
Two possible routes to fast and reliable quantum chemical modelling and simulations of large macromolecules are outlined; a wave-function-based and an electron-densitybased. In the former method, the NDDO (Neglect of Diatomic Differential Overlap) approximation, a widely used basis for many semi-empirical molecular orbital approaches is examined and a new model, overcoming the inherent deficiencies in the NDDO model is proposed. In the new model, first order correction term is added to the electron-electron Coulomb interactions, thereby improving the balance between the core-electron and the electron-electron interactions. Using the new model, non-empirical calculations are performed showing that the total energies from this model are consistently slightly higher than those from corresponding ab initio calculation but closer to the ab initio results than when the standard NDDO is used. Before introducing the latter scheme, current ab initio tight-binding methods, developed from density functional theory are overviewed. Thereafter some improvements, especially those leading to faster and more accurate integral evaluations developed in our group, are presented. Aeries of calculations on sample molecules show that the results from our ab initio tight-binding method have nearly the same accuracy as those obtained from the corresponding frozen-core density functional calculations but at much faster speed. Both methods, the extended NDDO and the ab initio tight-binding, show a great potential as future schemes to model and simulate macromolecular systems at ab initio level of accuracy but at the speed comparable to today's semi-empirical calculations.
Place, publisher, year, edition, pages
2006. Vol. 49, 315-341 p.
ab initio tight-binding, DFT, MD simulation, NDDO, Quantum Chemistry, Ab initio calculations, Macromolecular systems, Quantum-chemical modelling, Semi-empirical calculation, Tight binding, Binding energy, Density functional theory, Electron-electron interactions, Electrons, Macromolecules, Molecular orbitals, Calculations
Other Chemistry Topics
IdentifiersURN: urn:nbn:se:kth:diva-155010ScopusID: 2-s2.0-84880390704ISBN: 9783540255420OAI: oai:DiVA.org:kth-155010DiVA: diva2:761129
QC 201411052014-11-052014-10-292014-11-05Bibliographically approved