scholarly journals Erratum: A density functional approach to freezing transitions in molecular fluids: Dipolar hard spheres [J. Chem. Phys. 86, 4146 (1987)]

1988 ◽  
Vol 88 (2) ◽  
pp. 1476-1477 ◽  
Author(s):  
William E. McMullen ◽  
David W. Oxtoby
Keyword(s):  
Density Functional ◽  
Hard Spheres ◽  
Chem Phys ◽  
Functional Approach ◽  
Molecular Fluids

The structure of associating hard spheres adsorbed on crystalline solids: a density functional approach

1999 ◽  
Vol 96 (5) ◽  
pp. 885-892 ◽  
Author(s):  
R. ZAGÓRSKI ◽  
M. BORÓWKO ◽  
S. SOKOŁOWSKI ◽  
O. PIZIO
Keyword(s):  
Density Functional ◽  
Hard Spheres ◽  
Functional Approach ◽  
Crystalline Solids

A TWO-COMPONENT FLUID MIXTURE OF THE HARD SPHEROCYLINDERS

2011 ◽  
Vol 25 (02) ◽  
pp. 301-317 ◽  
Author(s):  
M. MORADI ◽  
R. KHORDAD
Keyword(s):  
Correlation Functions ◽  
Density Functional ◽  
Hard Spheres ◽  
Chem Phys ◽  
Nonspherical Particles ◽  
Fluid Mixture ◽  
Functional Theory ◽  
Fluid Mixtures ◽  
Hypernetted Chain ◽  
Hard Spherocylinders

We study a classical fluid mixture of nonspherical molecules. The components of the mixture are two kinds of the hard spherocylinders with different shape anisotropies L/D. Two different approaches are used to calculate the direct correlation functions (DCF) of this kind of fluids. First, we use a formalism based on the weighted density functional theory (WDFT), introduced by Chamoux and Perera [ J. Chem. Phys.104, 1493 (1996)]. Second, we describe a general approach solving the Percus–Yevick (PY) and the hypernetted chain integral equation numerically for the fluid mixtures of hard nonspherical particles. In the second approach, the pair, total, and DCF of binary molecular fluid mixtures can be calculated simultaneously whereas in the WDFT, the pair and the total correlation functions are calculated indirectly. The obtained correlation functions are compared using these two methods. The pressure of the fluid mixture is also calculated using the Fourier zero components of the DCFs and compared with the Monte Carlo simulation. Finally, the large and small shape anisotropy, are considered and the results are compared with the binary fluid mixture of hard ellipsoids and hard spheres. The results are fairly in agreement.

Effect of elastic constants of liquid crystals in their electro-optical properties

2017 ◽  
Vol 14 (11) ◽  
pp. 1750163
Author(s):  
Z. Parang ◽  
T. Ghaffary ◽  
M. M. Gharahbeigi
Keyword(s):  
Optical Properties ◽  
Liquid Crystals ◽  
Elastic Constants ◽  
Density Functional ◽  
Hard Spheres ◽  
Hard Core ◽  
Molecular Fluids ◽  
Dipolar Fluid ◽  
The Density Functional Theory ◽  
Complex Liquids

Recently following the success of the density functional theory (DFT) in obtaining the structure and thermodynamics of homogeneous and inhomogeneous classical systems such as simple fluids, dipolar fluid and binary hard spheres, this theory was also applied to obtain the density profile of a molecular fluid in between hard planar walls by Kalpaxis and Rickayzen. In the theory of molecular fluids, the direct correlation function (DCF) can be used to calculate the equation of state, free energy, phase transition, elastic constants, etc. It is well known that the hard core molecular models play an important role in understanding complex liquids such as liquid crystals. In this paper, a classical fluid of nonspherical molecules is studied. The required homogeneous (DCF) is obtained by solving Orenstein–Zernike (OZ) integral equation numerically. Some of the molecules in the liquid crystals have a sphere shape and this kind of molecular fluid is considered here. The DCF sphere of the molecular fluid is calculated and it will be shown that the results are in good agreement with the pervious works and the results of computer simulation. Finally the electro-optical properties of ellipsoid liquid crystal using DCF of these molecules are calculated.

Computational Investigation of the Asymmetry in Photosynthetic Reaction Center Models from First Principles

2020 ◽  
Author(s):  
Denis Artiukhin ◽  
Patrick Eschenbach ◽  
Johannes Neugebauer
Keyword(s):  
Spin Density ◽  
Reaction Center ◽  
Density Functional ◽  
Photosynthetic Reaction Center ◽  
Chem Phys ◽  
Molecular Structures ◽  
Error Characteristic ◽  
Molecular Systems ◽  
Density Distributions ◽  
The Asymmetry

We present a computational analysis of the asymmetry in reaction center models of photosystem I, photosystem II, and bacteria from <i>Synechococcus elongatus</i>, <i>Thermococcus vulcanus</i>, and <i>Rhodobacter sphaeroides</i>, respectively. The recently developed FDE-diab methodology [J. Chem. Phys., 148 (2018), 214104] allowed us to effectively avoid the spin-density overdelocalization error characteristic for standard Kohn–Sham Density Functional Theory and to reliably calculate spin-density distributions and electronic couplings for a number of molecular systems ranging from dimeric models in vacuum to large protein including up to about 2000 atoms. The calculated spin densities showed a good agreement with available experimental results and were used to validate reaction center models reported in the literature. We demonstrated that the applied theoretical approach is very sensitive to changes in molecular structures and relative orientation of molecules. This makes FDE-diab a valuable tool for electronic structure calculations of large photosynthetic models effectively complementing the existing experimental techniques.

`Diet GMKTN55' Offers Accelerated Benchmarking Through a Representative Subset Approach

2018 ◽  
Author(s):  
Tim Gould
Keyword(s):  
Density Functional ◽  
Chem Phys ◽  
Comprehensive Analysis ◽  
Genetic Approach ◽  
Representative Subset ◽  
Phys Chem Chem Phys

The GMTKN55 benchmarking protocol introduced by [Goerigk et al., Phys. Chem. Chem. Phys., 2017, 19, 32184] allows comprehensive analysis and ranking of density functional approximations with diverse chemical behaviours. But this comprehensiveness comes at a cost: GMTKN55's 1500 benchmarking values require energies for around 2500 systems to be calculated, making it a costly exercise. This manuscript introduces three subsets of GMTKN55, consisting of 30, 100 and 150 systems, as `diet' substitutes for the full database. The subsets are chosen via a stochastic genetic approach, and consequently can reproduce key results of the full GMTKN55 database, including ranking of approximations.

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