<i>Ab initio</i>Hartree-Fock Born effective charges of LiH, LiF, LiCl, NaF, and NaCl

Shukla, Alok

doi:10.1103/physrevb.61.13277

Cited by 12 publications

(4 citation statements)

References 42 publications

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“…The second large group of population analyses tries to access the atomic charges via observables of the molecule. Restrained Electrostatic Potential (RESP) charges are, for example, extracted from the electrostatic potential of the molecule, whereas the atomic-polar-tensor or Born effective charges are determined as derivatives of the electronic dipole moment with respect to nuclear displacements. − …”

Section: Introductionmentioning

confidence: 99%

Berry Population Analysis: Atomic Charges from the Berry Curvature in a Magnetic Field

Peters

Culpitt

Tellgren

et al. 2023

J. Chem. Theory Comput.

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The Berry curvature is essential in Born−Oppenheimer molecular dynamics, describing the screening of the nuclei by the electrons in a magnetic field. Parts of the Berry curvature can be understood as the external magnetic field multiplied by an effective charge so that the resulting Berry force behaves like a Lorentz force during the simulations. Here, we investigate whether these effective charges can provide insight into the electronic structure of a given molecule or, in other words, whether we can perform a population analysis based on the Berry curvature. To develop our approach, we first rewrite the Berry curvature in terms of charges that partially capture the effective charges and their dependencies on the nuclear velocities. With these Berry charges and charge fluctuations, we then construct our population analysis yielding atomic charges and overlap populations. Calculations at the Hartree−Fock level reveal that the atomic charges are similar to those obtained from atomic polar tensors. However, since we additionally obtain an estimate for the fluctuations of the charges and a partitioning of the atomic charges into contributions from all atoms, we conclude that the Berry population analysis is a useful alternative tool to analyze the electronic structures of molecules.

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Section: Introductionmentioning

confidence: 99%

Berry Population Analysis: Atomic Charges from the Berry Curvature in a Magnetic Field

Peters

Culpitt

Tellgren

et al. 2023

J. Chem. Theory Comput.

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“…We also present a plot of the Wannier functions in the substance as also the Mulliken population analysis to confirm the ionic bonding in Li 2 O. As far as LiCl is concerned, earlier, we computed its Born charge at the Hartree-Fock level using our Wannier function methodology 9 and found its value to be significantly smaller as compared to the experiments. Therefore, in this work, we perform correlated calculations of the Born charge of LiCl and, indeed, obtain much better agreement with the experiments.…”

Section: Introductionmentioning

confidence: 99%

Ab initioWannier-function-based correlated calculations of Born effective charges of crystallineLi2Oand LiCl

Sony

Shukla

2008

Phys. Rev. B

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In this paper, we have used our recently developed ab initio Wannier-function-based methodology to perform extensive Hartree-Fock and correlated calculations on Li 2 O and LiCl to compute their Born effective charges. Results thus obtained are in very good agreement with the experiments. In particular, for the case of Li 2 O, we resolve a controversy originating in the experiment of Osaka and Shindo ͓Solid State Commun. 51, 421 ͑1984͔͒ who had predicted the effective charge of Li ions to be in the range of 0.58-0.61, a value much smaller compared to its nominal value of unity, thereby, suggesting that the bonding in the material could be partially covalent. We demonstrate that effective charge computed by Osaka and Shindo is the Szigeti charge, and once the Born charge is computed, it is in excellent agreement with our computed value. Mulliken population analysis of Li 2 O also confirms ionic nature of the bonding in the substance.

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“…In the present study also we have used the lobe-type contracted Gaussian basis functions used in our earlier works. [9][10][11][12][13] Unit cell Wannier functions for both the materials were described using basis functions centered in cells as far as the third-nearest neighbors of the reference cell. 9,10 For LiH we performed the calculations using the optimized lattice constant 4.067 Å obtained in our earlier correlated calculation, 11 which is in excellent agreement with the experimental value of 4.06 Å.…”

Section: 10mentioning

confidence: 99%

“…11,12 Moreover, within the Berry-phase formalism of King-Smith and Vanderbilt, 4 we have also used our approach to compute the BECs of several ionic insulators at the HF level. 13 The purpose behind the present work is to use our Wannier-function-based methodology to perform correlated calculations of the BEC's of insulators. Since ours is a real-space approach, we start with the following expression for the electronic contribution to the polarization per unit cell (P e ) valid for insulators: 14…”

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confidence: 99%

Ab initioWannier-function-based many-body approach to Born charges of crystalline insulators

Sony

Shukla

2004

Phys. Rev. B

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In this paper we present an approach aimed at performing many-body calculations of Born-effective charges of crystalline insulators by including the electron-correlation effects. The scheme is implemented entirely in the real space, using Wannier functions as single-particle orbitals. Correlation effects are computed by including virtual excitations from the Hartree-Fock mean field, and the excitations are organized as per a BetheGoldstone-like many-body hierarchy. The results of our calculations suggest that the approach presented here is promising. The Born effective charge (BEC) of a periodic solid is an important phenomenological quantity which connects the electronic structure of the system to its phononic properties. 1Of late, in the context of ferroelectric materials and their phase transitions, BEC has generated tremendous amount of interest.2 Using BEC, one can also describe the lattice dynamics, and its coupling to infrared radiation, in a simple intuitive manner. 3 Most of the modern calculations of BECs are based upon the Berry-phase-based theory of macroscopic polarization developed by King-Smith and Vanderbilt. 4 The aforesaid formalism is based upon single-particle orbitals, and, therefore, can be implemented in a straightforward manner within ab initio density-functional theory (DFT), 2,3 or the Hartree-Fock (HF) framework.5 As far as many-body calculations of polarization properties are concerned, Martin and co-workers have proposed several approaches which, to the best of our knowledge, have not been implemented within an ab initio methodology. 6,7 Filippetti and Spaldin have recently implemented an ab initio method aimed at including correlation effects by using a self-interaction-corrected (SIC) density-functional approach. 8 Recently, we have developed a wave-function-based ab initio methodology aimed at performing electronic structure calculations on crystalline insulators. [9][10][11][12] The approach uses Wannier functions as single-particle orbitals obtained at the Hartree-Fock level, which can subsequently be used to include the electron correlation effects, if needed. The approach has been applied to calculate ground state geometries, cohesive energies, and elastic properties of crystalline insulators at the Hartree-Fock level, 9,10 as well as at the correlated level. 11,12 Moreover, within the Berry-phase formalism of King-Smith and Vanderbilt, 4 we have also used our approach to compute the BECs of several ionic insulators at the HF level. 13 The purpose behind the present work is to use our Wannier-function-based methodology to perform correlated calculations of the BEC's of insulators. Since ours is a real-space approach, we start with the following expression for the electronic contribution to the polarization per unit cell (P e ) valid for insulators: 14where is a parameter governing the state of crystal (for the present case, it represents atomic displacements), ⍀ is the volume of the unit cell, q e is the electronic charge, N͑→ϱ͒, represents the total number of unit cells in th...

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Ab initioHartree-Fock Born effective charges of LiH, LiF, LiCl, NaF, and NaCl

Cited by 12 publications

References 42 publications

Berry Population Analysis: Atomic Charges from the Berry Curvature in a Magnetic Field

Berry Population Analysis: Atomic Charges from the Berry Curvature in a Magnetic Field

Ab initioWannier-function-based correlated calculations of Born effective charges of crystallineLi2Oand LiCl

Ab initioWannier-function-based many-body approach to Born charges of crystalline insulators

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