Local <i>ab initio</i> methods for calculating optical bandgaps in periodic systems. II. Periodic density fitted local configuration interaction singles method for solids

Lorenz, Marco; Maschio, Lorenzo; Schütz, Martin; Usvyat, Denis

doi:10.1063/1.4767775

Cited by 17 publications

(20 citation statements)

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“…This new approach will be discussed in detail in a forthcoming article. 52 In the following we will present some first test calculations of CIS excitonic band gaps of the MgO and LiF crystals and explore how the band gaps depend on the diffuseness of the basis set. The use of atom-centered basis sets in periodic systems is generally a long-standing issue, 61 which does not yet have an ultimate solution.…”

Section: Excitonic Band Gaps Of Simple 3d Crystalsmentioning

confidence: 99%

Cryscor: a program for the post-Hartree–Fock treatment of periodic systems

Pisani

Schütz

Casassa

et al. 2012

Phys. Chem. Chem. Phys.

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127

200

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CRYSCOR is a periodic post-Hartree-Fock program based on local functions in direct space, i.e., Wannier functions and projected atomic orbitals. It uses atom centered Gaussians as basis functions. The Hartree-Fock reference, as well as symmetry information, is provided by the CRYSTAL program. CRYSCOR presently features an efficient and parallel implementation of periodic local second order Møller-Plesset perturbation theory (MP2), which allows us to study 1D-, 2D-and 3D-periodic systems beyond 1000 basis functions per unit cell. Apart from the correlation energy also the MP2 density matrix, and from that the Compton profile, are available. Very recently, a new module for calculating excitonic band gaps at the uncorrelated Configuration-Interaction-Singles (CIS) level has been added. Other advancements include new extrapolation techniques for calculating surface adsorption on semiinfinite solids. In this paper the diverse features and recent advances of the present CRYSCOR version are illustrated by exemplary applications to various systems: the adsorption of an argon monolayer on the MgO (100) surface, the rolling energy of a boron nitride nanoscroll, the relative stability of different aluminosilicates, the inclusion energy of methane in methane-ice-clathrates, and the effect of electron correlation on charge and momentum density of a-quartz. Furthermore, we present some first tentative CIS results for excitonic band gaps of simple 3D-crystals, and their dependence on the diffuseness of the basis set.

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Section: Excitonic Band Gaps Of Simple 3d Crystalsmentioning

confidence: 99%

Cryscor: a program for the post-Hartree–Fock treatment of periodic systems

Pisani

Schütz

Casassa

et al. 2012

Phys. Chem. Chem. Phys.

Self Cite

127

200

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“…In the following section, we show how it is computed in the full range of UV-visible energies for periodic systems, by slightly modifying the frequency-dependent CPHF(KS) method already implemented in the CRYSTAL code. The performance of the method, similar to the time-dependent Hartree-Fock (TDHF) method 9 or to the configuration interaction singles (CIS) method 10,11 as implemented in a molecular context, or to the time-dependent DFT (TDDFT) and equivalent Bethe-Salpeter equation (BSE), 12,13 as used for periodic compounds, is discussed in the present work by considering bulk Silicon (Si), SiC and LiF. The effect of the computational parameters controlling the calculation will be considered in the Si case for which high quality experimental results [14][15][16] and many previous computations 17 are available.…”

Section: Introductionmentioning

confidence: 99%

Ab Initio Calculation of the Ultraviolet–Visible (UV-vis) Absorption Spectrum, Electron-Loss Function, and Reflectivity of Solids

Ferrari

Orlando

Rérat

2015

J. Chem. Theory Comput.

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The field frequency has recently been taken into account in the coupled-perturbed HartreeFock or Kohn-Sham method implemented in the CRYSTAL code 1 for calculating the highfrequency dielectric constant of semi-conductors up to the first electronic transitions. In this work, we document how the code has been generalized and improved in order to compute the full UV-visible absorption spectrum, the electron loss function and the reflectivity from the real and imaginary parts of the electric response property. We show how spectra are modified when the crystalline orbital relaxation due to the dynamic electric field is taken into account, and how this modification increases with the percentage of Hartree-Fock exchange in the unperturbed hybrid hamiltonian.

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“…Local approximations further enhance the efficiency of calculations, since the assembly for each pair involves only pair-domain-restricted set of indices. The local restrictions can be imposed on the auxiliary index as well, 21,66,95,96,98,99 bringing further savings.…”

Section: Local Density Fitting For 4-index Integralsmentioning

confidence: 99%

“…In this work, we adapt the direct-space local density fitting technique, developed earlier for the periodic LMP2 66 and CIS 99 methods, to the two-electron integrals of the periodic local F12 theory. Consider a general two-electron integral (irR|Î 12 |j J sS) (written in the chemical notation) with a multiplicative operator kernel I 12 , which is the case for the integrals…”

Section: Local Density Fitting For 4-index Integralsmentioning

confidence: 99%

“…Alternative technique for calculating these integrals, applied also in this work, is density fitting (DF) approximation, 64,66,[90][91][92][93][94][95][96][97][98][99] which decomposes the 4-index integrals into contractions of 3-index quantities. This method, although not reducing the nominal scaling of the integral evaluation, allows for much more efficient treatment even in the canonical case.…”

Section: Local Density Fitting For 4-index Integralsmentioning

confidence: 99%

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Linear-scaling explicitly correlated treatment of solids: Periodic local MP2-F12 method

Usvyat

2013

The Journal of Chemical Physics

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Linear scaling explicitly correlated MP2-F12 and ONIOM methods for the long-range interactions of the nanoscale clusters in methanol aqueous solutions J. Chem. Phys. 138, 014106 (2013) Theory and implementation of the periodic local MP2-F12 method in the 3*A fixed-amplitude ansatz is presented. The method is formulated in the direct space, employing local representation for the occupied, virtual, and auxiliary orbitals in the form of Wannier functions (WFs), projected atomic orbitals (PAOs), and atom-centered Gaussian-type orbitals, respectively. Local approximations are introduced, restricting the list of the explicitly correlated pairs, as well as occupied, virtual, and auxiliary spaces in the strong orthogonality projector to the pair-specific domains on the basis of spatial proximity of respective orbitals. The 4-index two-electron integrals appearing in the formalism are approximated via the direct-space density fitting technique. In this procedure, the fitting orbital spaces are also restricted to local fit-domains surrounding the fitted densities. The formulation of the method and its implementation exploits the translational symmetry and the site-group symmetries of the WFs. Test calculations are performed on LiH crystal. The results show that the periodic LMP2-F12 method substantially accelerates basis set convergence of the total correlation energy, and even more so the correlation energy differences. The resulting energies are quite insensitive to the resolution-of-the-identity domain sizes and the quality of the auxiliary basis sets. The convergence with the orbital domain size is somewhat slower, but still acceptable. Moreover, inclusion of slightly more diffuse functions, than those usually used in the periodic calculations, improves the convergence of the LMP2-F12 correlation energy with respect to both the size of the PAO-domains and the quality of the orbital basis set. At the same time, the essentially diffuse atomic orbitals from standard molecular basis sets, commonly utilized in molecular MP2-F12 calculations, but problematic in the periodic context, are not necessary for LMP2-F12 treatment of crystals. © 2013 AIP Publishing LLC.

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Local ab initio methods for calculating optical bandgaps in periodic systems. II. Periodic density fitted local configuration interaction singles method for solids

Cited by 17 publications

References 78 publications

Cryscor: a program for the post-Hartree–Fock treatment of periodic systems

Cryscor: a program for the post-Hartree–Fock treatment of periodic systems

Ab Initio Calculation of the Ultraviolet–Visible (UV-vis) Absorption Spectrum, Electron-Loss Function, and Reflectivity of Solids

Linear-scaling explicitly correlated treatment of solids: Periodic local MP2-F12 method

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