Anisotropy of the elastic properties of crystalline cellulose Iβ from first principles density functional theory with Van der Waals interactions

The elastic properties of rutile transition metal dioxides XO2 ( X = Ru , Rh , Os , and Ir ) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO 2 and IrO 2 show strong incompressibility. The hardness estimated for these dioxides shows that they are not superhard solids. The obtained Debye temperatures are comparative to those of transition metal dinitrides or diborides.

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First-principles study of the structural and elastic properties of Ti5Si3 with substitutions Zr, V, Nb, and Cr

Journal of Materials Research ◽

10.1557/jmr.2010.0293 ◽

2010 ◽

Vol 25 (12) ◽

pp. 2317-2324 ◽

Cited By ~ 9

Author(s):

Hui-Yuan Wang ◽

Wen-Ping Si ◽

Shi-Long Li ◽

Nan Zhang ◽

Qi-Chuan Jiang

Keyword(s):

Density Functional Theory ◽

Elastic Properties ◽

First Principles ◽

Electronic Structures ◽

Density Functional ◽

Elastic Moduli ◽

Site Occupancy ◽

Formation Enthalpy ◽

Functional Theory ◽

The Density Functional Theory

The formation enthalpy, electronic structures, and elastic moduli of the intermetallic compound Ti5Si3 with substitutions Zr, V, Nb, and Cr are investigated by using first-principles methods based on the density-functional theory. Our calculation shows that the site occupancy behaviors of alloying elements in Ti5Si3, determined by their atom radius, are consistent with the available experimental observations. Furthermore, using the Voigt–Reuss–Hill (VRH) approximation method, we obtained the bulk modulus B, shear modulus G, and the Young’s modulus E. Among these four substitutions, the V, Nb, and Cr substitutions can improve the ductility of Ti5Si3 effectively, while Zr substitution has little effect on the elastic properties of Ti5Si3. The elastic property variations of Ti5Si3 due to different substitutions are found to be correlated with the Me4d–Me4d antibonding and the strengthened Me4d–Si bonding in the solids.

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ADSORPTION OF THIOPHENE ON N-DOPED TiO2/MoS2 NANOCOMPOSITES INVESTIGATED BY VAN DER WAALS CORRECTED DENSITY FUNCTIONAL THEORY

Surface Review and Letters ◽

10.1142/s0218625x18500385 ◽

2018 ◽

Vol 25 (01) ◽

pp. 1850038

Author(s):

AMIRALI ABBASI ◽

JABER JAHANBIN SARDROODI

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Van Der Waals ◽

Titanium Atom ◽

Density Functional Theory Calculations ◽

Van Der Waals Interactions ◽

Functional Theory ◽

Structural And Electronic Properties ◽

Potential Applicability ◽

Thiophene Molecule

Comparison of structural and electronic properties between pristine and N-doped titanium dioxide-(TiO2)/molybdenum disulfide (MoS2) nanocomposites and their effects on the adsorption of thiophene molecule were performed using density functional theory calculations. To correctly estimate the adsorption energies, the van der Waals interactions were taken into account in the calculations. On the TiO2/MoS2 nanocomposite, thiophene molecule tends to be strongly adsorbed by its sulfur atom. The five-fold coordinated titanium atom of TiO2 was found to be an active binding site for thiophene adsorption. The results suggest that the thiophene molecule has not any mutual interaction with MoS2 nanosheet. The electronic structures of the complex systems are discussed in terms of the density of states and molecular orbitals of the thiophene molecules adsorbed to the TiO2/MoS2 nanocomposites. It was also found that the doping of nitrogen atom is conductive to the interaction of thiophene with nanocomposite. Thus, it can be concluded that the interaction of thiophene with N-doped TiO2/MoS2 nanocomposite is more energetically favorable than the interaction with undoped nanocomposite. The sensing capability of TiO2/MoS2 toward thiophene detection was greatly increased upon nitrogen doping. These processes ultimately lead to the strong adsorption of thiophene on the N-doped TiO2/MoS2 nanocomposites, indicating potential applicability of these nanocomposites as novel gas sensors.

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