Generalized energy‐based fragmentation approach for modeling condensed phase systems

Abstract

We have extended the generalized energy‐based fragmentation (GEBF) method to condensed phase systems with periodic boundary condition (PBC). The so‐called PBC‐GEBF method provides an alternative way of calculating electronic structures of condensed phase systems, whose accuracy is comparable to standard periodic electronic structure methods for some types of condensed phase systems such as molecular crystals and ionic liquid crystals. Within the PBC‐GEBF approach, the unit cell energy (or properties) of a condensed phase system can be evaluated as a linear combination of ground‐state energies (or corresponding properties) of a series of electrostatically embedded subsystems, which can be routinely calculated with existing molecular quantum chemistry packages. With the PBC‐GEBF approach, one can routinely perform ab initio calculations at post‐Hartree–Fock levels, including Møller–Plesset perturbation theory (MP2) or coupled cluster singles and doubles, on certain types of condensed phase systems, in which periodic post‐Hartree–Fock methods are not available or not feasible computationally. This review will offer an overview of the methodology and implementation of the PBC‐GEBF method and its applications in predicting the structures, lattice energies, and vibrational spectra of a wide range of molecular and ionic liquid crystals. Our results show that the PBC‐GEBF approach at post‐Hartree–Fock theory level can generally provide highly accurate descriptions on the structure and properties of crystals under study. For example, the vibrational spectra of the crystalline BH3NH3 predicted by the PBC‐GEBF approach at the MP2 level are in better agreement with the experimentally observed spectra, than those based on density functional theory calculations. WIREs Comput Mol Sci 2017, 7:e1297. doi: 10.1002/wcms.1297 This article is categorized under: Structure and Mechanism > Molecular Structures

Recent developments in symmetry‐adapted perturbation theory

“…The first-order SRS correction, Equation (11), is a sum of E 1 ð Þ RS and the first-order exchange energy E 1 ð Þ exch which is positive for the interaction of two closed-shell systems. At short range, E 1 ð Þ exch provides the primary source of repulsion between any two molecules-the electrons from A and B are discouraged from occupying the same space as the Pauli exclusion principle prevents all of them to reside in the same orbital.…”

“…2 Noncovalent interactions are not only ubiquitous, but they are also absolutely necessary to describe many physical, chemical, and biochemical phenomena, ranging from thermodynamics of nonideal gases to spectroscopy and scattering cross sections of interstellar complexes to the performance and selectivity (including enantioselectivity) of molecular catalysts to the secondary, tertiary, and quaternary structure of proteins, the double-helix structure of DNA, and the interaction between enzymes and their substrates (or inhibitors). Thus, theoretical and experimental investigations of noncovalent interactions are published in very large quantities, and various aspects of these interactions have been reviewed in this journal [3][4][5][6][7][8][9][10][11][12][13][14][15] and elsewhere. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] From the theoretical standpoint, the interaction energy E int between two subsystems A and B is usually computed within the supermolecular approach 33 :…”

Fast quantum chemistry calculations for large molecules and condensed-phase systems: The developments and applications of generalized energy-based fragmentation approach

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Embedded, graph‐theoretically defined many‐body approximations for wavefunction‐in‐DFT and DFT‐in‐DFT: Applications to gas‐ and condensed‐phase ab initio molecular dynamics, and potential surfaces for quantum nuclear effects

“…Methods that employ this idea are often presented as embedding or fragmentation approaches. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] These approaches are complementary to the intensive work on many-body methods [28][29][30][31][32][33][34][35][36] that have also greatly contributed towards the development of reduced scaling methods. These methods have allowed localized treatments of correlation with larger basis sets with substantial computational cost reductions and often in a manner that is trivially parallelizable.…”