Extremely localized molecular orbitals: theory and applications

Localized orbitals for molecular calculations

We present an overview of the existing localization algorithms which have been or are being used to perform quantum chemical molecular calculations that take into account electronic correlation effects. The natural distinction between intrinsic and extrinsic localization methods is explained and developed. The advantages and drawbacks of specific methods are discussed in terms of CPU time requi...

Unitary Optimization of Localized Molecular Orbitals.

A unified formalism and its implementation is presented for Foster-Boys, fourth moment, Pipek-Mezey, and Edmiston-Ruedenberg type localization schemes of molecular orbitals through unitary optimization of the localizing transform matrix using a recently proposed algorithm [ Abrudan ; et al. Signal Processing 2009 , 89 , 1704 ]. A conjugate gradient algorithm is used with an efficient line searc...

Topological Localized Molecular Orbitals of Hiickel and Mobius Annulenes*

A localization method in the framework of Ruckel MO theory which relies only on molecular topology, and which can be regarded to as the topological version of well established localization criteria, has been applied to the series of (n)annulenes. The calculations have been effected for both Ruckel and Mobius topologies, and several aspects of the resulting localized orbitals (homogeneity, equiv...

On the Relationship. Between Localized Molecular Orbitals and Kekule Structures*

Localized molecular orbitals for n-systems of conjugated polycyclic hydrocarbons have been calculated using both intrinsic and external localization criteria relying only on molecular topology. For benzenoid aromatic compounds the intrinsic localized molecular orbital arrangement can always be associated to the Kekule structure of maximal Kekule index value. However hydrocarbons containing four...

Reformulating Time-Dependent Density Functional Theory (TDDFT) with Non-orthogonal Localized Molecular Orbitals