Attractive short-range interatomic potential in the lattice dynamics of niobium and tantalum

1987 ◽  
Vol 9 (6) ◽  
pp. 647-656 ◽  
Author(s):  
B. N. Onwuagba ◽  
S. Pal
Keyword(s):  
Lattice Dynamics ◽  
Short Range ◽  
Interatomic Potential

Lattice dynamics of ionic molecular crystals in the rigid ion approximation, phases II and III of sodium superoxide

1984 ◽  
Vol 62 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Pier Francesco Fracassi ◽  
Michael L. Klein ◽  
Raffaele Guido Della Valle
Keyword(s):  
Experimental Data ◽  
Computer Program ◽  
Long Range ◽  
Lattice Dynamics ◽  
Short Range ◽  
Molecular Crystals ◽  
Electrostatic Potentials ◽  
Wave Method ◽  
Long Wave

Quasi-harmonic lattice dynamics is developed for ionic molecular crystals, within the framework of the rigid ion approximation. Long-range electrostatic potentials as well as short-range atom–atom interactions are discussed, making extensive use of the Ewald long wave method. A computer program based on this theory has been developed, and phonon calculations have been carried out for phases II and III of solid Na+O2−. The calculated quantities are then compared with experimental data.

scholarly journals SIMULATIONS OF COLLISION CASCADES IN Cu–Nb LAYERED COMPOSITES USING AN EAM INTERATOMIC POTENTIAL

2009 ◽  
Vol 01 (03) ◽  
pp. 421-442 ◽  
Author(s):  
M. J. DEMKOWICZ ◽  
R. G. HOAGLAND
Keyword(s):  
Short Range ◽  
Interatomic Potential ◽  
Ion Bombardment ◽  
Embedded Atom Method ◽  
Layered Composites ◽  
Orientation Relation ◽  
Embedded Atom

The embedded atom method (EAM) is used to construct an interatomic potential for modelling interfaces in Cu – Nb nanocomposites. Implementation of the Ziegler–Biersack–Littmark (ZBL) model for short-range interatomic interactions enables studies of response to ion bombardment. Collision cascades are modelled in fcc Cu , bcc Nb , and in Cu – Nb layered composites in the experimentally-observed Kurdjumov–Sachs (KS) orientation relation. The interfaces in these composites reduce the number of vacancies and interstitials created per keV of the primary knock-on atom (PKA) by 50–70% compared to fcc Cu or bcc Nb .

scholarly journals Lattice Dynamics of YBa2Cu3O6+x (x = 0·25, 0·5, 0.75)

1993 ◽  
Vol 46 (4) ◽  
pp. 535 ◽  
Author(s):  
KK Yim ◽  
J Oitmaa ◽  
MM Elcombe
Keyword(s):  
Oxygen Concentration ◽  
Density Of States ◽  
Coulomb Potential ◽  
Lattice Dynamics ◽  
Short Range ◽  
Phonon Dispersion ◽  
Normal Modes ◽  
Phonon Density ◽  
Phonon Density Of States ◽  
Phonon Dispersion Curves

The lattice dynamics of YBa2Cu306+x with partially filled 0(4) sites is investigated using a supercell method. The model used is the lattice-dynamical shell model, which incorporates the short-range interactions and the long-range Coulomb potential as well as the polarisabilities of ions. Varying the oxygen content produces small changes throughout the spectrum of normal modes, as well as major changes in those modes with large 0(4) amplitudes. Selected phonon dispersion curves are presented, with emphasis on the variation of frequency with oxygen concentration. The nature of new modes, which appear with an increase in oxygen concentration, is investigated. The overall phonon density of states is also presented.

Effect of polarizability on the vibrational and thermal properties of rare gas solids

1978 ◽  
Vol 56 (7) ◽  
pp. 849-858 ◽  
Author(s):  
S. K. Jain ◽  
G. P. Srivastava
Keyword(s):  
Lattice Dynamics ◽  
Interatomic Potential ◽  
Phonon Dispersion ◽  
Zero Point ◽  
Rare Gas ◽  
Model Parameters ◽  
Point Energy ◽  
Phonon Dispersion Curves ◽  
Boundary Frequency ◽  
Experimental Values

A simple shell model theory has been developed for the study of lattice dynamics of monatomic crystals. The phonon dispersion curves and variations of heat capacities with temperature are reported for solidified krypton and argon. The model parameters have been evaluated using the recent experimental values of elastic constants, polarizability of atoms, and a zone boundary frequency in each case. The zero point effects are also included by expressing the zero point energy in terms of the interatomic potential. The agreement between the theoretical and experimental results is found to improve appreciably by incorporating polarizability of atoms.

PECULIARITIES OF VIBRATION CHARACTERISTICS OF AMORPHOUS ICES

2012 ◽  
Vol 01 (01) ◽  
pp. 1250008 ◽  
Author(s):  
KIRILL V. GETS ◽  
OLEG S. SUBBOTIN ◽  
VLADIMIR R. BELOSLUDOV
Keyword(s):  
Lattice Dynamics ◽  
Short Range ◽  
Dynamic Properties ◽  
Water Molecules ◽  
Disordered Phase ◽  
Amorphous Ices ◽  
Simulation Cell ◽  
Dynamics Simulations ◽  
Localized Vibrations ◽  
Very High

Dynamic properties of low (LDA), high (HDA) and very high (VHDA) density amorphous ices were investigated within the approach based on Lattice Dynamics simulations. In this approach, we assume that the short-range molecular order mainly determines the dynamic and thermodynamic properties of amorphous ices. Simulation cell of 512 water molecules with periodical boundary conditions and disordering allows us to study dynamical properties and dispersion curves in the Brillouin zone of pseudo-crystal. Existence of collective phenomena in amorphous ices which is usual for crystals but anomalous for disordered phase was confirmed in our simulations. Molecule amplitudes of delocalized (collective) as well as localized vibrations have been considered.

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