VBEFP: A Valence Bond Approach That Incorporates Effective Fragment Potential Method

Abstract

An ab initio explicit solvation valence bond (VB) method, called VBEFP, is presented. The VBEFP method is one type of QM/MM approach in which the QM part of system is treated within the ab initio valence bond scheme and the solvent water molecules are accounted by the effective fragment potential (EFP) method, which is a polarized force field approach developed by Gordon et al. (J. Chem. Phys. 1996, 105, 1968). This hybrid method enables one to take the first-solvation shell and heterogeneous solvation effects into account explicitly with VB wave function. Therefore, the nature of chemical bonding and the mechanism of chemical reactions with explicit solvent environments can be explored at the ab inito VB level. In this paper, the hydrated metal-ligand complexes [M(2+)L](H(2)O)(n) (M(2+): Mg(2+), Zn(2+); L: NH(3), CH(2)O) are studied by the VBEFP method. Resonance energy and bond order are computed, and the influence of the solvent coordination and hydrogen bonding to the metal-ligand bonding are explored in the paper.

Valence Bond‐Based Hybrid Quantum Mechanics Molecular Mechanics Approaches and Proper Inclusion of the Effect of the Surroundings

“…These included methods that treat the environment as a continuum model, such as VBPCM [56] and VBSM. Ab initio methods with explicit description of the environment include: the VBEFP, which, due to the EFP1 method involved, is still limited to reactivity in solvents; [81] and the MOVB, which uses localized MOs on predefined fragments and is, thus, relatively efficient computationally but, at the same time, cannot provide classical VB description and, depending on the structures chosen, may have redundancy. In addition, even with homogeneous solvents the description is not complete, since the fine details of the solvent are missing, and these methods cannot properly describe, for example, reorganization and non-equilibrium effects.…”

“…The ideas of VB/MM and, in particular, DE-VB/MM led Wu and coworkers to develop the VB effective fragment potential (VBEFP) method, [81] which combines ab initio VB calculations [73] with explicit solvent effects described by the effective fragment potential (EFP) method, [82][83][84][85] using the QM/MM formalism.…”

XMVB 2.0: A new version of Xiamen valence bond program

“…The VBEFP method [14] is one type of QM/MM approach using explicit solvent models. In VBEFP, the QM part of the system is treated within an ab initio VB scheme, while the MM part are represented by the EFP approach, which is a polarizable force field approach.…”

“…[11] Moreover, several newly developed hybrid VB methods are implemented in XMVB 2.0 by embedding XMVB into GAMESS. [12] These methods include VB polarizable continuum model (VBPCM) method, [13] VB effective fragment potential (VBEFP) method, [14] density-functional-based VB (DFVB) method [15] and the VBSCF method for complete active space [VBSCF(CAS)]. [16] Another feature of XMVB 2.0 is the use of Fortran 90 in coding, instead of Fortran 77 in XMVB 1.0.…”

Valence: A Massively Parallel Implementation of the Variational Subspace Valence Bond Method

“…The variety of methods has broadened to include breathing orbital VB, the block‐localized wave function method, and MOVB, among others. VB has been combined with molecular mechanics (MM/VB) and effective fragment potentials (VBEFP) . Many methods are incorporated into the VB2000 and XMVB packages .…”