Abhilash Patra, Subrata Jana, **Lucian A** **Constantin**, Prasanjit Samal,

The meta-generalized-gradient approximation (meta-GGA) of the exchange-correlation energy functional can provide appealing performance for the wide range of quantum chemistry and solid-state properties. So far, several meta-GGAs are proposed by fitting to the test sets or/and satisfying as many as known exact constraints. Although the density overlap is treated by ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2020, 153(8):084117]

Cited: 0 times

Szymon Śmiga, **Lucian A** **Constantin**,

We show that accurate exchange-correlation hybrid functionals give very physically optimized effective-correlation potentials, capable of correctly describing the quantum oscillations of atoms and molecules. Based on this analysis and on understanding the error cancellation between semilocal exchange and correlation functionals, we propose a very simple, semilocal correlation potential model compatible ... **Read more >>**

J Phys Chem A (The journal of physical chemistry. A)

[2020, 124(27):5606-5614]

Cited: 0 times

Szymon Śmiga, **Lucian A** **Constantin**,

The modified point charge plus continuum (mPC) model **[Constantin,** L. A.; Phys. Rev. B 2019, 99, 085117] solves the important failures of the original counterpart, namely, the divergences when the reduced gradient of the density is large, such as in the tail of the density and in quasi-dimensional density regimes. ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2020, 16(8):4983-4992]

Cited: 0 times

Abhilash Patra, Subrata Jana, **Lucian A** **Constantin**, Letizia Chiodo, Prasanjit Samal,

Nonuniform density scaling in the quasi-two-dimensional (quasi-2D) regime is an important and challenging aspect of the density functional theory. Semilocal exchange-correlation energy functionals, developed by solving the dimensional crossover criterion in the quasi-2D regime, have great theoretical and practical importance. However, the only semilocal generalized gradient approximation (GGA) that has ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2020, 152(15):151101]

Cited: 0 times

Subrata Jana, **Lucian A** **Constantin**, Prasanjit Samal,

Accurate prediction of the water properties from a low-cost ab initio method is still a foremost problem for chemists and physicists. Although density functional approaches starting from semilocal to hybrid exchange-correlation functionals are tested, they are not efficiently performing for all the properties together, especially considering energies, conformal ranking, structures, ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2020, 16(2):974-987]

Cited: 0 times

Subrata Jana, Abhilash Patra, **Lucian A** **Constantin**, Prasanjit Samal,

Due to their quantitative accuracy and ability to solve several difficulties, screened range-separated hybrid exchange-correlation functionals are now a standard approach for ab initio simulation of condensed matter systems. However, the screened range-separated hybrid functionals proposed so far are biased either toward compact or slowly varying densities. In this paper, ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2020, 152(4):044111]

Cited: 0 times

**Lucian A** **Constantin**, Eduardo Fabiano, Fabio Della Sala,

We assess several generalized gradient approximations (GGAs) and Laplacian-level meta-GGAs (LL-MGGA) kinetic energy (KE) functionals for orbital-free density functional theory calculations of bulk metals and semiconductors, considering equilibrium distances, bulk moduli, total and kinetic energies, and the electron densities. We also considered the effects of the pseudopotentials, the vacancy formation ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2019, 15(5):3044-3055]

Cited: 0 times

**Lucian A** **Constantin**, Eduardo Fabiano, Fabio Della Sala,

Kinetic energy (KE) approximations are key elements in orbital-free density functional theory. To date, the use of nonlocal functionals, possibly employing system-dependent parameters, has been considered mandatory in order to obtain satisfactory accuracy for different solid-state systems, whereas semilocal approximations are generally regarded as unfit to this aim. Here, we ... **Read more >>**

J Phys Chem Lett (The journal of physical chemistry letters)

[2018, 9(15):4385-4390]

Cited: 2 times

**Lucian A** **Constantin**, Eduardo Fabiano, Fabio Della Sala,

Using the semiclassical neutral atom theory, we developed a modified fourth-order kinetic energy (KE) gradient expansion (GE4m) that keeps unchanged all the linear-response terms of the uniform electron gas and gives a significant improvement with respect to the known semilocal functionals for both large atoms and jellium surfaces. On the ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2017, 13(9):4228-4239]

Cited: 1 time

Szymon Śmiga, Eduardo Fabiano, **Lucian A** **Constantin**, Fabio Della Sala,

The development of semilocal models for the kinetic energy density (KED) is an important topic in density functional theory (DFT). This is especially true for subsystem DFT, where these models are necessary to construct the required non-additive embedding contributions. In particular, these models can also be efficiently employed to replace ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2017, 146(6):064105]

Cited: 3 times

**Lucian A** **Constantin**, Eduardo Fabiano, Fabio Della Sala,

We introduce a novel non-local ingredient for the construction of exchange density functionals: the reduced Hartree parameter, which is invariant under the uniform scaling of the density and represents the exact exchange enhancement factor for one- and two-electron systems. The reduced Hartree parameter is used together with the conventional meta-generalized ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2016, 145(8):084110]

Cited: 0 times

Szymon Śmiga, Eduardo Fabiano, Savio Laricchia, **Lucian A** **Constantin**, Fabio Della Sala,

We analyze the methodology and the performance of subsystem density functional theory (DFT) with meta-generalized gradient approximation (meta-GGA) exchange-correlation functionals for non-bonded molecular systems. Meta-GGA functionals depend on the Kohn-Sham kinetic energy density (KED), which is not known as an explicit functional of the density. Therefore, they cannot be directly ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2015, 142(15):154121]

Cited: 2 times

Eduardo Fabiano, **Lucian A** **Constantin**, Pietro Cortona, Fabio Della Sala,

We propose global hybrid approximations of the exchange-correlation (XC) energy functional which reproduce well the modified fourth-order gradient expansion of the exchange energy in the semiclassical limit of many-electron neutral atoms and recover the full local density approximation (LDA) linear response. These XC functionals represent the hybrid versions of the ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2015, 11(1):122-131]

Cited: 3 times

Aleksandrs Terentjevs, Paolo E Trevisanutto, **Lucian A** **Constantin**, Fabio Della Sala,

The optical spectra of the β-SiC(0 0 1)/Al interface has been studied using first principles time-dependent density functional theory. We considered the bare random phase approximation as well as two different exchange-correlation kernels, i.e. the adiabatic-local-density-approximation and the jellium-with-gap kernel of Trevisanutto et al (2013 Phys. Rev. B 87 205143). ... **Read more >>**

J Phys Condens Matter (Journal of physics. Condensed matter : an Institute of Physics journal)

[2014, 26(26):265006]

Cited: 0 times

Eduardo Fabiano, Paolo E Trevisanutto, Aleksandrs Terentjevs, **Lucian A** **Constantin**,

We studied uniform electron gas with a gap model in the context of density functional theory. On the basis of this analysis, we constructed two local gap models that are used in generalized gradient approximation (GGA) correlation functionals that satisfy numerous exact constraints for correlation energy. The first one, named ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2014, 10(5):2016-2026]

Cited: 2 times

Savio Laricchia, **Lucian A** **Constantin**, Eduardo Fabiano, Fabio Della Sala,

We tested Laplacian-level meta-generalized gradient approximation (meta-GGA) noninteracting kinetic energy functionals based on the fourth-order gradient expansion (GE4). We considered several well-known Laplacian-level meta-GGAs from the literature (bare GE4, modified GE4, and the MGGA functional of Perdew and **Constantin** (Phys. Rev. B 2007,75, 155109)), as well as two newly designed ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2014, 10(1):164-179]

Cited: 11 times

**Lucian A** **Constantin**, E Fabiano, F Della Sala,

We construct a meta-generalized-gradient approximation which properly balances the nonlocality contributions to the exchange and correlation at the semilocal level. This nonempirical functional shows good accuracy for a broad palette of properties (thermochemistry, structural properties) and systems (molecules, metal clusters, surfaces, and bulk solids). The accuracy for several well-known problems ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2013, 9(5):2256-2263]

Cited: 14 times

**Lucian A** **Constantin**, Eduardo Fabiano, Fabio Della Sala,

We discuss, simplify, and improve the spin-dependent correction of **Constantin** et al. [Phys. Rev. B 84, 233103 (2011)] for atomization energies, and develop a density parameter of the form v ∝ |∇n|/n(10/9), found from the statistical ensemble of one-electron densities. The here constructed exchange-correlation generalized gradient approximations (GGAs), named zvPBEsol ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2012, 137(19):194105]

Cited: 5 times

Letizia Chiodo, **Lucian A** **Constantin**, Eduardo Fabiano, Fabio Della Sala,

We construct a generalized gradient approximation of the exchange-correlation energy that satisfies the nonuniform scaling in one dimension and is accurate in the whole quasi-two-dimensional (Q2D) regime. Using spatial and energetic analyses of metal (111) surfaces, we show that the Q2D behavior is important at the surface of most transition ... **Read more >>**

Phys. Rev. Lett. (Physical review letters)

[2012, 108(12):126402]

Cited: 6 times

E Fabiano, **Lucian A** **Constantin**, F Della Sala,

We assess the performance of the whole class of functionals defined by the Perdew-Burke-Ernzerhof (PBE) exchange-correlation enhancement factor, by performing a two-dimensional scan of the μ and κ parameters (keeping β fixed by the recovery of the local density approximation linear response). We consider molecular (atomization energies, bond lengths, and ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2011, 7(11):3548-3559]

Cited: 16 times

E Fabiano, **Lucian A** **Constantin**, F Della Sala,

We compare the performance of different exchange-correlation functionals, based on the Perdew-Burke-Ernzerhof (PBE) generalized gradient approximation, for the structural and electronic properties of gold nanostructures. In particular we consider PBEsol (constructed to correctly describe solid-state systems) and PBEint [Phys. Rev. B 82, 113104 (2010)] which was recently introduced for hybrid ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2011, 134(19):194112]

Cited: 5 times

**Lucian A** **Constantin**, E Fabiano, S Laricchia, F Della Sala,

We use the asymptotic expansions of the semiclassical neutral atom as a reference system in density functional theory to construct accurate generalized gradient approximations (GGAs) for the exchange-correlation and kinetic energies without any empiricism. These asymptotic functionals are among the most accurate GGAs for molecular systems, perform well for solid ... **Read more >>**

Phys. Rev. Lett. (Physical review letters)

[2011, 106(18):186406]

Cited: 20 times

**Lucian A** **Constantin**, John C Snyder, John P Perdew, Kieron Burke,

By extrapolating the energies of nonrelativistic atoms and their ions with up to 3000 electrons within Kohn-Sham density functional theory, we find that the ionization potential remains finite and increases across a row of the periodic table, even as Z → ∞. The local density approximation for the exchange contribution ... **Read more >>**

J Chem Phys (The Journal of chemical physics)

[2010, 133(24):241103]

Cited: 3 times

John P Perdew, Adrienn Ruzsinszky, Gábor I Csonka, **Lucian A** **Constantin**, Jianwei Sun,

Semilocal density functionals for the exchange-correlation energy are needed for large electronic systems. The Tao-Perdew-Staroverov-Scuseria (TPSS) meta-generalized gradient approximation (meta-GGA) is semilocal and usefully accurate, but predicts too-long lattice constants. Recent "GGA's for solids" yield good lattice constants but poor atomization energies of molecules. We show that the construction principle ... **Read more >>**

Phys. Rev. Lett. (Physical review letters)

[2009, 103(2):026403]

Cited: 98 times

John P Perdew, Adrienn Ruzsinszky, **Lucian A** **Constantin**, Jianwei Sun, Gábor I Csonka,

Some fundamental issues in ground-state density functional theory are discussed without equations: (1) The standard Hohenberg-Kohn and Kohn-Sham theorems were proven for a Hamiltonian that is not quite exact for real atoms, molecules, and solids. (2) The density functional for the exchange-correlation energy, which must be approximated, arises from the ... **Read more >>**

J Chem Theory Comput (Journal of chemical theory and computation)

[2009, 5(4):902-908]

Cited: 61 times

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