Empirical van der Waals corrections to solid-state density functional theory: Iodine and phosphorous containing molecular crystals

2012 ◽  
Vol 33 (19) ◽  
pp. 1615-1622 ◽  
Author(s):  
John Kendrick ◽  
Frank J. J. Leusen ◽  
Marcus A. Neumann
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Density Functional ◽  
Van Der Waals ◽  
Molecular Crystals ◽  
State Density ◽  
Functional Theory

Evaluation of the Lattice Energy of the Two-Component Molecular Crystals Using Solid-State Density Functional Theory

2014 ◽  
Vol 14 (10) ◽  
pp. 4997-5003 ◽  
Author(s):  
Mikhail V. Vener ◽  
Elena O. Levina ◽  
Oleg A. Koloskov ◽  
Alexey A. Rykounov ◽  
Alexander P. Voronin ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Density Functional ◽  
Molecular Crystals ◽  
Lattice Energy ◽  
State Density ◽  
Functional Theory ◽  
Two Component

Identifying and explaining vibrational modes of quinacridones via temperature-resolved terahertz spectroscopy: absorption experiments and solid-state density functional theory simulations

2020 ◽  
Vol 22 (35) ◽  
pp. 19672-19679 ◽  
Author(s):  
A. D. Squires ◽  
Adam J. Zaczek ◽  
R. A. Lewis ◽  
Timothy M. Korter
Keyword(s):  
Density Functional Theory ◽  
Solid State ◽  
Density Functional ◽  
Terahertz Spectroscopy ◽  
State Density ◽  
Spectral Features ◽  
Thermal Contraction ◽  
Vibrational Modes ◽  
Functional Theory

New spectral features and anomalous shifting of vibrational modes of beta quinacridone are revealed, unusual thermal contraction the likely origin.

Terahertz spectroscopy and solid-state density functional theory calculations of structural isomers: Nicotinic acid, isonicotinic acid and 2-picolinic acid

2017 ◽  
Vol 31 (13) ◽  
pp. 1750149 ◽  
Author(s):  
Ling Ding ◽  
Wen-Hui Fan ◽  
Xu Chen ◽  
Ze-You Chen ◽  
Chao Song
Keyword(s):  
Density Functional Theory ◽  
Nicotinic Acid ◽  
Density Functional ◽  
Isonicotinic Acid ◽  
Picolinic Acid ◽  
Molecular Crystals ◽  
Density Functional Theory Calculations ◽  
State Density ◽  
Functional Theory ◽  
Absorption Features

We report, for the first time to our knowledge, the terahertz (THz) spectra of isonicotinic acid and 2-picolinic acid. The distinct THz spectral differences among these two isomers and nicotinic acid have also been observed, indicating that the THz vibrational modes are highly sensitive to the structural differences even in similar molecular crystals. Besides, solid-state density functional theory calculations reveal better qualitative agreement with the measured absorption features, which are related to the molecular vibrations of nicotinic acid and isonicotinic acid. As for 2-picolinic acid, the calculation based on the primitive cell reproduces the absorption features at 1.46, 1.82 and 2.46 THz originating from intermolecular vibrations. These results suggest that THz spectra can identify the complex intermolecular interactions even in similar molecular crystals, which shows potential applications in identifying isomers in food and pharmaceutical production.

scholarly journals Van der Waals Density Functional Theory vdW-DFq for Semihard Materials

Crystals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 243 ◽  
Author(s):  
Qing Peng ◽  
Guangyu Wang ◽  
Gui-Rong Liu ◽  
Suvranu De
Keyword(s):  
Density Functional Theory ◽  
Energetic Materials ◽  
Density Functional ◽  
Energetic Material ◽  
Van Der Waals ◽  
Molecular Crystals ◽  
Soft Materials ◽  
Dispersion Force ◽  
Electronic Charge ◽  
Functional Theory

There are a large number of materials with mild stiffness, which are not as soft as tissues and not as strong as metals. These semihard materials include energetic materials, molecular crystals, layered materials, and van der Waals crystals. The integrity and mechanical stability are mainly determined by the interactions between instantaneously induced dipoles, the so called London dispersion force or van der Waals force. It is challenging to accurately model the structural and mechanical properties of these semihard materials in the frame of density functional theory where the non-local correlation functionals are not well known. Here, we propose a van der Waals density functional named vdW-DFq to accurately model the density and geometry of semihard materials. Using β -cyclotetramethylene tetranitramine as a prototype, we adjust the enhancement factor of the exchange energy functional with generalized gradient approximations. We find this method to be simple and robust over a wide tuning range when calibrating the functional on-demand with experimental data. With a calibrated value q = 1.05 , the proposed vdW-DFq method shows good performance in predicting the geometries of 11 common energetic material molecular crystals and three typical layered van der Waals crystals. This success could be attributed to the similar electronic charge density gradients, suggesting a wide use in modeling semihard materials. This method could be useful in developing non-empirical density functional theories for semihard and soft materials.

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