AUTHOR=Ying Fuming , Zhou Chen , Zheng Peikun , Luan Jiamin , Su Peifeng , Wu Wei 

TITLE=λ-Density Functional Valence Bond: A Valence Bond-Based Multiconfigurational Density Functional Theory With a Single Variable Hybrid Parameter

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 7 - 2019

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00225

DOI=10.3389/fchem.2019.00225

ISSN=2296-2646

ABSTRACT=A new valence bond (VB) based multireference density functional theory (MRDFT) method, named λ-DFVB, is presented in this paper. The method follows the idea of the hybrid multi-reference density-functional method theory proposed by Toulouse et al (J. Chem. Phys., 2012, 137, 044104). λ-DFVB combines valence bond self-consistent field (VBSCF) method with KS-DFT by decomposing the electron-electron interactions with a hybrid parameter λ. Different from the Toulouse’s scheme, the hybrid parameter λ in λ-DFVB is variable, defined as a function of a multi-reference character of a molecular system. Furthermore, the EC correlation energy of a leading determinant is introduced to ensure size-consistency at the dissociation limit. Satisfactory results of test calculations, including potential energy surfaces, bond dissociation energies, reaction barriers, and singlet-triplet energy gaps, show the potential capability of λ-DFVB for molecular systems with strong correlation.