Density functional theory in classical explicit solvents: Mean‐field QM / MM method for simulating solid–liquid interfaces

2022 ◽  
Author(s):  
Taehwan Jang ◽  
Dooam Paik ◽  
Seung‐Jae Shin ◽  
Hyungjun Kim
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Mean Field ◽  
Liquid Interfaces ◽  
Functional Theory ◽  
Solid Liquid

scholarly journals Charge radii of potassium isotopes in the RMF(BCS)* approach

2022 ◽  
Author(s):  
Rong An ◽  
Shisheng Zhang ◽  
Li-Sheng Geng ◽  
Feng-Shou 张丰收 Zhang
Keyword(s):  
Experimental Data ◽  
Density Functional Theory ◽  
Density Functional ◽  
Mean Field ◽  
Field Studies ◽  
Nuclear Density ◽  
Isotopic Chain ◽  
Functional Theory ◽  
Charge Radii ◽  
Nuclear Density Functional Theory

Abstract We apply the recently proposed RMF(BCS)* ansatz to study the charge radii of the potassium isotopic chain up to $^{52}$K. It is shown that the experimental data can be reproduced rather well, qualitatively similar to the Fayans nuclear density functional theory, but with a slightly better description of the odd-even staggerings (OES). Nonetheless, both methods fail for $^{50}$K and to a lesser extent for $^{48,52}$K. It is shown that if these nuclei are deformed with a $\beta_{20}\approx-0.2$, then one can obtain results consistent with experiments for both charge radii and spin-parities. We argue that beyond mean field studies are needed to properly describe the charge radii of these three nuclei, particularly for $^{50}$K.

scholarly journals Grand-Canonical Approach to Density Functional Theory of Electrocatalytic Systems: Thermodynamics of Solid-Liquid Interfaces at Constant Ion and Electrode Potentials

2018 ◽  
Author(s):  
Marko Melander ◽  
Mikael Kuisma ◽  
Thorbjørn Christensen ◽  
Karoliina Honkala
Keyword(s):  
Density Functional ◽  
Canonical Ensemble ◽  
Coarse Graining ◽  
Grand Canonical Ensemble ◽  
Liquid Interfaces ◽  
Functional Theory ◽  
Electrode Potentials ◽  
Solid Liquid ◽  
Electrochemical Interfaces ◽  
Grand Canonical

Properties of solid-liquid interfaces are of immense importance for electrocatalytic and electrochemical systems but modelling such interfaces at the atomic level presents a serious challenge and approaches beyond standard methodologies are needed. An atomistic computational scheme needs treat at least part of the system quantum mechanically to include adsorption and reactions while the entire system is in thermal equilibrium. The experimentally relevant macroscopic control variables are temperature, electrode potential, choice of the solvent and ions and these need to be explicitly included in the computational model as well; this calls for an thermodynamic ensemble with fixed ion and electrode potentials. In this work a general framework within density functional theory with fixed electron and ion chemical potentials in the grand canonical ensemble is established for modelling electrocatalytic and electrochemical interfaces. Starting from a fully quantum mechanical description of nuclei and electrons, a systematic coarse-graining is employed to establish various computational schemes including i) the combination of classical and electronic density functional theories within the grand canonical ensemble and ii) on the simplest level a chemically and physically sound way to obtain the (modified) Poisson-Boltzmann (mPB) implicit solvent model. The detailed and rigorous derivation clearly establishes which approximations are needed for coarse-graining as well as highlights which details and interactions are omitted in vein of computational feasibility. The transparent approximations also allow removing some the constraints and coarse-graining if needed. We implement various mPB models in the GPAW code and test their capabilities to model capacitance of electrochemical interfaces as well as study different approaches for modelling partly periodic charged systems. Our rigorous and well-defined DFT coarse-graining scheme to continuum electrolytes highlights the inadequacy of current linear dielectric models for treating properties of the electrochemical interface.<br><br>

scholarly journals Grand-Canonical Approach to Density Functional Theory of Electrocatalytic Systems: Thermodynamics of Solid-Liquid Interfaces at Constant Ion and Electrode Potentials

2018 ◽  
Author(s):  
Marko Melander ◽  
Mikael Kuisma ◽  
Thorbjørn Christensen ◽  
Karoliina Honkala
Keyword(s):  
Density Functional ◽  
Canonical Ensemble ◽  
Coarse Graining ◽  
Grand Canonical Ensemble ◽  
Liquid Interfaces ◽  
Functional Theory ◽  
Electrode Potentials ◽  
Solid Liquid ◽  
Electrochemical Interfaces ◽  
Grand Canonical

Properties of solid-liquid interfaces are of immense importance for electrocatalytic and electrochemical systems but modelling such interfaces at the atomic level presents a serious challenge and approaches beyond standard methodologies are needed. An atomistic computational scheme needs treat at least part of the system quantum mechanically to include adsorption and reactions while the entire system is in thermal equilibrium. The experimentally relevant macroscopic control variables are temperature, electrode potential, choice of the solvent and ions and these need to be explicitly included in the computational model as well; this calls for an thermodynamic ensemble with fixed ion and electrode potentials. In this work a general framework within density functional theory with fixed electron and ion chemical potentials in the grand canonical ensemble is established for modelling electrocatalytic and electrochemical interfaces. Starting from a fully quantum mechanical description of nuclei and electrons, a systematic coarse-graining is employed to establish various computational schemes including i) the combination of classical and electronic density functional theories within the grand canonical ensemble and ii) on the simplest level a chemically and physically sound way to obtain the (modified) Poisson-Boltzmann (mPB) implicit solvent model. The detailed and rigorous derivation clearly establishes which approximations are needed for coarse-graining as well as highlights which details and interactions are omitted in vein of computational feasibility. The transparent approximations also allow removing some the constraints and coarse-graining if needed. We implement various mPB models in the GPAW code and test their capabilities to model capacitance of electrochemical interfaces as well as study different approaches for modelling partly periodic charged systems. Our rigorous and well-defined DFT coarse-graining scheme to continuum electrolytes highlights the inadequacy of current linear dielectric models for treating properties of the electrochemical interface.<br><br>

Demixing and ordering in Ni(Ti,Zr)(Sb,Sn) half-Heusler materials

2017 ◽  
Vol 19 (45) ◽  
pp. 30695-30702 ◽  
Author(s):  
Joaquin Miranda Mena ◽  
Thomas Gruhn
Keyword(s):  
Density Functional Theory ◽  
Monte Carlo ◽  
Phase Separation ◽  
Monte Carlo Simulations ◽  
Density Functional ◽  
Field Model ◽  
Mean Field ◽  
Study Phase ◽  
Mean Field Model ◽  
Functional Theory

We employed density functional theory, Monte Carlo simulations and a mean field model to study phase separation in thermoelectric Ni(Ti,Zr)(Sb,Sn) half-Heusler materials, simultaneously alloyed in the (Ti,Zr)- and (Sb,Sn) sublattices.

QUASILOCAL DENSITY FUNCTIONAL THEORY FOR NUCLEI INCLUDING PAIRING CORRELATIONS

2007 ◽  
Vol 16 (02) ◽  
pp. 249-262 ◽  
Author(s):  
X. VIÑAS ◽  
V. I. TSELYAEV ◽  
V. B. SOUBBOTIN ◽  
S. KREWALD
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Equations Of Motion ◽  
Mean Field ◽  
Field Operator ◽  
Functional Theory ◽  
Hartree Fock ◽  
Orbit Potential ◽  
The Density Functional Theory ◽  
Pairing Correlations

We propose first a generalization of the Density Functional Theory leading to single-particle equations of motion with a quasilocal mean-field operator containing a position-dependent effective mass and a spin-orbit potential. Ground-state properties of doubly magic nuclei are obtained within this framework using the Gogny D1S force and compared with the exact Hartree-Fock values. Next, extend the Density Functional Theory to include pairing correlations without formal violation of the particle-number condition. This theory, which is nonlocal, is simplified by a suitable quasilocal reduction. Some calculations to show the ability of this theory are presented.

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