scholarly journals Lattice Dynamics of Simple Harmonic and Anharmonic Shell Models

1967 ◽  
Vol 20 (5) ◽  
pp. 495 ◽  
Author(s):  
J Oitmaa
Keyword(s):  
Dipole Moment ◽  
Shell Model ◽  
Lattice Dynamics ◽  
Higher Order ◽  
Force Constants ◽  
Dynamical Equations ◽  
Normal Coordinates ◽  
Shell Models ◽  
Rigid Ion Model ◽  
Explicit Expressions

The lattice dynamics of harmonic and anharmonic shell models are reviewed. It is shown that the various dynamical equations for the shell model can be expressed in the same form as those for the rigid ion model, but with modified force constants. The anharmonic shell model leads to higher order contributions to the dipole moment, quadratic and cubic in the normal coordinates, for which explicit expressions are obtained.

Gitterdynamik von Verbindungen mit Matlockit-Struktur / Lattice Dynamics of Compounds with Matlockite-Type Structure

1984 ◽  
Vol 39 (8) ◽  
pp. 783-788 ◽  
Author(s):  
H. Haeuseler ◽  
G. Schneider
Keyword(s):  
Lattice Dynamics ◽  
Short Range ◽  
Force Constants ◽  
Type Structure ◽  
Short Range Force ◽  
Model Lattice ◽  
Range Force ◽  
Rigid Ion Model

On the basis of the rigid ion model and polarizable ion model, lattice dynamical calculations have been carried out for the fluorohalides BaFCl and BaFBr and for the oxyhalides LaOCl, LaOBr, YOCl, SmOCl and GdOCl which crystallize with the tetragonal Matlockite-type structure (PbFCl-type). The results of these calculations: short range force constants, effective dynamical charges and polarizabilities are communicated and discussed. Bonding in the fluorohalides is much more ionic than in the oxyhalides.

Rigid ion model of lattice dynamics - A re-evaluation

1971 ◽  
Vol 9 (3) ◽  
pp. 185-189 ◽  
Author(s):  
K.V. Namjoshi ◽  
S.S. Mitra ◽  
J.F. Vetelino
Keyword(s):  
Lattice Dynamics ◽  
Rigid Ion Model

Theoretical dipole moment derivatives and force constants for HCN

1978 ◽  
Vol 69 (4) ◽  
pp. 1425-1428 ◽  
Author(s):  
B. Liu ◽  
K. M. Sando ◽  
C. S. North ◽  
H. B. Friedrich ◽  
D. M. Chipman
Keyword(s):  
Dipole Moment ◽  
Force Constants

Analytical higher-order-theories for noise reduction analysis of viscoelastic composite multilayered shells

2021 ◽  
pp. 095440622098233
Author(s):  
A Alaimo ◽  
C Orlando ◽  
S Valvano
Keyword(s):  
Sound Transmission ◽  
Higher Order ◽  
Sound Insulation ◽  
Viscoelastic Layer ◽  
Multilayered Structures ◽  
Viscoelastic Composite ◽  
Damping Behavior ◽  
Shell Models ◽  
Composite Layers ◽  
Insulation Effect

The noise transmission of aeronautical panels is an important phase of the design process of an airplane. In this work an analytical Navier-type solution, based on higher-order layer-wise shell models, is proposed for the analysis of the sound insulation of laminated panels. The considered multilayered structures are laminated with cross-ply composite layers embedded with interlaminar viscoelastic sheets. The use of the soft interlayers permits to have a passive insulation effect in the study of the sound transmission. In order to take into account the frequency depedent properties of a realistic viscoelastic layer, the damping behavior is modeled through a fractional derivative Zener model. The Rayleigh integral method is used to extrapolate the acoustic indicators for the sound transmission analysis. Some results are presented to validate the efficiency of the present approach, comparing the present solutions with others taken from the literature.

Equivalence Between Higher-Order Stress Power and Heat Flux in Energy Equation Based on Lattice Dynamics

1999 ◽  
Vol 121 (2) ◽  
pp. 240-246 ◽  
Author(s):  
Y. Yasui ◽  
K. Shizawa ◽  
K. Takahashi
Keyword(s):  
Heat Flux ◽  
Lattice Dynamics ◽  
Energy Equation ◽  
Solid Mechanics ◽  
Higher Order ◽  
First Law Of Thermodynamics ◽  
Internal Forces ◽  
Order Stress ◽  
As Stress

The essence of macroscopic quantities in solid mechanics can be grasped by expressing these quantities in terms of kinematic and mechanical quantities of atoms. In this paper, a method is proposed for obtaining the microscopic definitions of internal forces of continua such as stress, higher-order stresses and heat flux. Moreover, the relation between higher-order stress power and heat flux is discussed expressing the first law of thermodynamics with microscopic quantities in the mesodomain. Comparing heat flux with higher-order stress power, it is clarified that the divergence of heat flux is equivalent to the total of each order power due to higher-order stresses.

Lattice dynamics study on cubic barium titanate based upon a modified rigid-shell model

1998 ◽  
Vol 206 (1) ◽  
pp. 219-230
Author(s):  
N. Takesue ◽  
H. Kubo ◽  
Haydn Chen
Keyword(s):  
Barium Titanate ◽  
Shell Model ◽  
Lattice Dynamics ◽  
Rigid Shell

The quantum theory of lattice dynamics. III

1969 ◽  
Vol 310 (1500) ◽  
pp. 101-109 ◽  
Keyword(s):  
Quantum Theory ◽  
Lattice Dynamics ◽  
Electronic Contribution ◽  
Body Interaction ◽  
Rigid Ion Model

The electronic contribution to the dynamical tensors is examined in more detail and the following results are obtained. First the electronic contribution is shown to be translationally invariant, secondly the assumption that this term can be approximately represented by a two-body interaction is shown to be equivalent to a rigid ion model, and finally this approximation is shown to become exact in the limit q = 0.

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