Cohesive energy-lattice constant and bulk modulus-lattice constant relationships: Alkali halides, Ag halides, Tl halides

1992 ◽  
Vol 53 (6) ◽  
pp. 855-856 ◽  
Author(s):  
Herbert Schlosser
2008 ◽  
Vol 22 (25) ◽  
pp. 2481-2492 ◽  
Author(s):  
VOICU DOLOCAN ◽  
ANDREI DOLOCAN ◽  
VOICU OCTAVIAN DOLOCAN

We present theoretical expressions relating the cohesive energy to the bulk modulus, the force constant and the lattice constant applicable to solids with a variety of crystal structures. We have found that the cohesive energy is directly proportional to the ratio between the product of the bulk modulus through the atomic volume and the exponent of the repulsion term. We have defined a figure of merit for materials as the ratio between the product of the bulk modulus through the atomic volume and the cohesive energy. The reciprocal of this ratio is a measure of the hardness of materials. Likewise, we have found the expressions for anharmonicity and thermal expansion coefficients, which can explain, also, their possible negative values.


1988 ◽  
Vol 141 ◽  
Author(s):  
J.-H. Xu

AbstractThe electronic structure of Al3V vs its two different crystal structures (DO22 and Ll2) were investigated using local density total energy approach. The calculated results of the total energy showed that in Al3V the tetragonal DO22 phase is energetically favored as compared to the cubic Ll2 phase, the total energy in the former case is about 60 mRy/F.U. lower than that in the later case. The calculated lattice constant (a=3.72 Å, c=8.20 Å) is in fairly good agreement with experiment (a=3.778 Å, c=8.326 Å),and the bulk modulus (1.3 Mbar) is comparable with the experimental Young modulus (150 GPa) for Al3Ti. Furthermore, it is interesting to note that the density of states at EF in the tetragonal DO22 phase (0.14 states/eV-F.U.) is about one order magnitude smaller than that in the Ll2 phase (2.89 states/eV-F.U.). The electronic structure of Al3V seems to be fairly satisfactory in explaining its phase stability.


2013 ◽  
Vol 664 ◽  
pp. 672-676
Author(s):  
De Ming Han ◽  
Gang Zhang ◽  
Li Hui Zhao

We present first-principles investigations on the elastic properties of XBi (X=Ho, Er) compounds. Basic physical properties, such as lattice constant, elastic constants (Cij), isotropic shear modulus (G), bulk modulus (B), Young’s modulus (Y), Poisson’s ratio (υ), and Anisotropy factor (A) are calculated. The calculated energy band structures show that the two compounds possess semi-metallic character. We hope that these results would be useful for future work on two compounds.


2004 ◽  
Vol 18 (25) ◽  
pp. 1301-1309 ◽  
Author(s):  
ANDREI DOLOCAN ◽  
VOICU OCTAVIAN DOLOCAN ◽  
VOICU DOLOCAN

By using a new Hamiltonian of interaction we have calculated the interaction energy for two-dimensional and three-dimensional lattices. We present also, approximate analytical formulae and the analytical formulae for the constant of the elastic force. The obtained results show that in the three-dimensional space, the two-dimensional lattice has the lattice constant and the cohesive energy which are smaller than that of the three-dimensional lattice. For appropriate values of the coupling constants, the two-dimensional lattice in a two-dimensional space has both the lattice constant and the cohesive energy, larger than that of the two-dimensional lattice in a three-dimensional space; this means that if there is a two-dimensional space in the Universe, this should be thinner than the three-dimensional space, while the interaction forces should be stronger. On the other hand, if the coupling constant in the two-dimensional lattice in the two-dimensional space is close to zero, the cohesive energy should be comparable with the cohesive energy from three-dimensional space but this two-dimensional space does not emit but absorbs radiation.


Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2932
Author(s):  
Jianhong Dai ◽  
Dongye He ◽  
Yan Song

First principles calculations were carried out to study the equilibrium properties of metals, including the electrons at bonding critical point; ebcp; cohesive energy; Ecoh; bulk modulus; B; and, atomic volume; V. 44 pure metals, including the s valence (alkali), p valence (groups III to V), and d valence (transition) metals were selected. In the present work, the electronic structure parameter ebcp has been considered to be a bridge connecting with the equilibrium properties of metals, and relationships between ebcp and equilibrium properties (V; Ecoh; and B) are established. It is easy to estimate the equilibrium properties (Ecoh; V, and B) of pure metals through proposed formulas. The relationships that were derived in the present work might provide a method to study the intrinsic mechanisms of the equilibrium properties of alloys and to develop new alloys.


2002 ◽  
Vol 14 (38) ◽  
pp. 8787-8793 ◽  
Author(s):  
R Gaudoin ◽  
W M C Foulkes ◽  
G Rajagopal
Keyword(s):  

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