Efficiency of Various Lattices from Hard Ball to Soft Ball:  Theoretical Study of Thermodynamic Properties of Dendrimer Liquid Crystal from Atomistic Simulation

In this work, we systematically studied the structural, electronic, magnetic, mechanical and thermodynamic properties of the fully compensated spin-gapless inverse Heusler Ti2MnAl compound under pressure strain condition by applying the first-principles calculation based on density functional theory and the quasi-harmonic Debye model. The obtained structural, electronic and magnetic behaviors without pressure are well consistent with previous studies. It is found that the spin-gapless characteristic is destroyed at 20 GPa and then restored with further increase in pressure. While, the fully compensated ferromagnetism shows a better resistance against the pressure up to 30 GPa and then becomes to non-magnetism at higher pressure. Tetragonal distortion has also been investigated and it is found the spin-gapless property is only destroyed when c/a is less than 1 at 95% volume. Three independent elastic constants and various moduli have been calculated and they all show increasing tendency with pressure increase. Additionally, the pressure effects on the thermodynamic properties under different temperature have been studied, including the normalized volume, thermal expansion coefficient, heat capacity at constant volume, Grüneisen constant and Debye temperature. Overall, this theoretical study presents a detailed analysis of the physical properties’ variation under strain condition from different aspects on Ti2MnAl and, thus, can provide a helpful reference for the future work and even inspire some new studies and lead to some insight on the application of this material.

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Theoretical Study of Solvent Effects on the Electronic and Thermodynamic Properties of Tetrathiafulvalene (TTF) Molecule Based on DFT

Asian Journal of Research and Reviews in Physics ◽

10.9734/ajr2p/2021/v5i230162 ◽

2021 ◽

pp. 42-54

Author(s):

Rabiu Nuhu Muhammad ◽

N. M. Mahraz ◽

A. S Gidado ◽

A. Musa

Keyword(s):

Thermodynamic Properties ◽

Bond Length ◽

Density Functional ◽

Theoretical Study ◽

Energy Gap ◽

Basis Set ◽

Basis Sets ◽

Frontier Molecular Orbital ◽

Orbital Energy ◽

Chemical Hardness

Tetrathiafulvalene () is an organosulfur compound used in the production of molecular devices such as switches, sensors, nonlinear optical devices and rectifiers. In this work, a theoretical study on the effects of solvent on TTF molecule was investigated and reported based on Density Functional Theory (DFT) as implemented in Gaussian 03 package using B3LYP/6-31++G(d,p) basis set. Different solvents were introduced as a bridge to investigate their effects on the electronic structure. The HUMO, LUMO, energy gap, global chemical index, thermodynamic properties, NLO and DOS analysis of the TTF molecule in order to determine the reactivity and stability of the molecule were obtained. The results obtained showed that the solvents have effects on the electronic and non-linear-optical properties of the molecule. The optimized bond length revealed that the molecule has strong bond in gas phase with smallest bond length of about 1.0834Å than in the rest of the solvents. It was observed that the molecule is more stable in acetonitrile with HOMO-LUMO gap and chemical hardness of 3.6373eV and 1.8187eV respectively. This indicates that the energy gap and chemical hardness of TTF molecule increases with the increase in polarity and dielectric constant of the solvents. The computed results agreed with the results in the literature. The thermodynamics and NLO properties calculation also indicated that TTF molecule has highest value of specific heat capacity (Cv), total dipole moment () and first order hyperpolarizability () in acetonitrile, while acetone has the highest value of entropy and toluene has a slightly higher value of zero point vibrational energy (ZPVE) than the rest of the solvents. The results show that careful selection of the solvents and basis sets can tune the frontier molecular orbital energy gap of the molecule and can be used for molecular device applications.

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Complex Hydrides Li<sub>2</sub>MH<sub>5</sub> (M = B, Al) for Hydrogen Storage Application: Theoretical Study of Structure, Vibrational Spectra and Thermodynamic Properties

International Journal of Computational and Theoretical Chemistry ◽

10.11648/j.ijctc.20150306.13 ◽

2015 ◽

Vol 3 (6) ◽

pp. 58 ◽

Cited By ~ 1

Author(s):

Melkizedeck Hiiti Tsere ◽

Tatiana P. Pogrebnaya ◽

Alexander M. Pogrebnoi

Keyword(s):

Thermodynamic Properties ◽

Hydrogen Storage ◽

Vibrational Spectra ◽

Theoretical Study ◽

Complex Hydrides

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Theoretical study of anisotropic structural, electronic, mechanical and thermodynamic properties of rare-earth (R = Y, La) oxysulfides

Computational Materials Science ◽

10.1016/j.commatsci.2016.08.050 ◽

2016 ◽

Vol 125 ◽

pp. 154-167 ◽

Cited By ~ 1

Author(s):

Y.F. Li ◽

B. Xiao ◽

Y.M. Gao ◽

Y.H. Cheng

Keyword(s):

Rare Earth ◽

Thermodynamic Properties ◽

Theoretical Study

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Theoretical study of the surface anchoring effect on the full leaky waveguide mode of liquid crystal

Chinese Journal of Liquid Crystals and Displays ◽

10.3788/yjyxs20183306.0483 ◽

2018 ◽

Vol 33 (6) ◽

pp. 483-489

Author(s):

孙婷婷 SUN Ting-ting ◽

袁瑞 YUAN Rui ◽

李振杰 LI Zhen-jie ◽

朱吉亮 ZHU Ji-liang ◽

邢红玉 XING Hong-yu ◽

...

Keyword(s):

Liquid Crystal ◽

Waveguide Mode ◽

Theoretical Study ◽

Surface Anchoring ◽

Anchoring Effect ◽

Leaky Waveguide

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Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.16.65 ◽

2020 ◽

Vol 16 ◽

pp. 674-680 ◽

Cited By ~ 1

Author(s):

Zeguo Fang ◽

Nawaf Al-Maharik ◽

Peer Kirsch ◽

Matthias Bremer ◽

Alexandra M Z Slawin ◽

...

Keyword(s):

Liquid Crystal ◽

Liquid Crystals ◽

Thermodynamic Properties ◽

Organic Liquid ◽

Dielectric Anisotropy ◽

Structure Property ◽

Structure Property Relationships

This paper describes the synthesis of a series of organic liquid crystals (LCs) containing selectively fluorinated cyclopropanes at their termini. The syntheses used difluorocarbene additions to olefin precursors, an approach which proved straightforward such that these liquid crystal candidates could be efficiently prepared. Their physical and thermodynamic properties were evaluated and depending on individual structures, they either displayed positive or negative dielectric anisotropy. The study gives some guidance into effective structure–property relationships for the design of LCs containing selectively fluorinated cyclopropane motifs.

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