UNIGE document Doctoral Thesis
previous document  unige:28678  next document
add to browser collection
Title

New methods to treat strongly correlated systems

Author
Directors
Defense Thèse de doctorat : Univ. Genève, 2013 - Sc. 4535 - 2013/01/22
Abstract This thesis focuses on development of three novel multiconfigurational quantum chemical methods, to study strongly correlated systems: GASSCF, SplitCAS and SplitGAS. By GASSCF it is possible to eliminate ineffective configurations from the CI expansion by choosing an arbitrary number of active spaces and by tuning the interspace excitations. By SplitCAS and SplitGAS, the CI wave function generated by CAS or GAS type of active spaces is partitioned into two parts: a principal part containing few relevant configurations and an extended part containing less relevant configurations. The two methods differ in the criteria for the splitting. Lowdin's partitioning technique is used to reduce the secular problem to the size of the principal space. These methods allow for an enlargement of the active space with respect to the CASSCF method. Theory, algorithmic details and test calculations are presented. Based on this work, the ‘scaling catastrophe' of the CASSCF approach is partially solved.
Keywords CASSCFMulticonfigurationalCorrelation energyActive spaceThe chromium dimer
Identifiers
URN: urn:nbn:ch:unige-286789
Full text
Thesis (12.7 MB) - public document Free access
Structures
Citation
(ISO format)
LI MANNI, Giovanni. New methods to treat strongly correlated systems. Université de Genève. Thèse, 2013. https://archive-ouverte.unige.ch/unige:28678

385 hits

366 downloads

Update

Deposited on : 2013-06-24

Export document
Format :
Citation style :