Hard Vibrational Modes Which Are, or Are Not, Induced to Condense by the Condensation of Soft Modes. Extension of the Concept of Faintness Index for Ferroelectricity and Ferroelasticity

1974 ◽  
Vol 37 (4) ◽  
pp. 885-896 ◽  
Author(s):  
Kêitsiro Aizu
Keyword(s):  
Vibrational Modes ◽  
Soft Modes

Structural relaxation in glassy polymers predicted by soft modes: a quantitative analysis

Soft Matter ◽  
2014 ◽  
Vol 10 (42) ◽  
pp. 8533-8541 ◽  
Author(s):  
Anton Smessaert ◽  
Jörg Rottler
Keyword(s):  
Quantitative Analysis ◽  
Computer Simulations ◽  
Structural Relaxation ◽  
Glassy Polymers ◽  
Low Energy ◽  
Vibrational Modes ◽  
Thermal Polymer ◽  
Soft Modes ◽  
Polymer Glass

We present a quantitative analysis of the correlation between quasi-localized, low energy vibrational modes and structural relaxation events in computer simulations of a quiescent, thermal polymer glass.

Anomalous vibrational modes in acetanilide as studied by inelastic neutron scattering

1992 ◽  
Vol 2 (10) ◽  
pp. 1929-1939 ◽  
Author(s):  
Mariette Barthes ◽  
Juegen Eckert ◽  
Susanna W. Johnson ◽  
Jacques Moret ◽  
Basil I. Swanson ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Vibrational Modes

Soft-modes in displacive transitions

1971 ◽  
Vol 32 (8-9) ◽  
pp. 657-670 ◽  
Author(s):  
S. Aubry ◽  
R. Pick
Keyword(s):  
Soft Modes

Complex formation and kinematic coupling: C2H4.PtCl3

1988 ◽  
Vol 53 (10) ◽  
pp. 2377-2384 ◽  
Author(s):  
Roman Řeřicha ◽  
Björg N. Cyvin ◽  
Jon Brunvoll ◽  
Sven J. Cyvin
Keyword(s):  
Complex Formation ◽  
Crystallographic Data ◽  
System Modelling ◽  
Vibrational Modes ◽  
Normal Coordinate ◽  
Kinematic Coupling ◽  
Fundamental Frequencies

Normal coordinate analyses including calculations of PED's were performed for C2H4.PtCl3 system modelling Zeise's anion, [(C2H4)PtCl3]-. The wedgewise distorsion of the C2H4 ligand known from the crystallographic data for Zeise's salt, was taken into account. Under these circumstances it was found that the kinematic couplings between the internal ligand and complex framework vibrational modes are rather small. The reliability of some existing assignments of the fundamental frequencies of Zeise's anion is discussed.

Asymptotics of the eigenmodes and stability of an elastic structure with general feedback matrix

2019 ◽  
Vol 84 (5) ◽  
pp. 873-911 ◽  
Author(s):  
Marianna A Shubov ◽  
Laszlo P Kindrat
Keyword(s):  
Initial Boundary ◽  
Initial Boundary Value Problem ◽  
Control Input ◽  
Vibrational Modes ◽  
Boundary Feedback ◽  
Feedback Matrix ◽  
Dissipative Boundary ◽  
Initial Boundary Value ◽  
The Right ◽  
Euler Bernoulli Beam

Abstract The distribution of natural frequencies of the Euler–Bernoulli beam subject to fully non-dissipative boundary conditions is investigated. The beam is clamped at the left end and equipped with a 4-parameter ($\alpha ,\beta ,k_1,k_2$) linear boundary feedback law at the right end. The $2 \times 2$ boundary feedback matrix relates the control input (a vector of velocity and its spatial derivative at the right end), to the output (a vector of shear and moment at the right end). The initial boundary value problem describing the dynamics of the beam has been reduced to the first order in time evolution equation in the state Hilbert space equipped with the energy norm. The dynamics generator has a purely discrete spectrum (the vibrational modes) denoted by $\{\nu _n\}_{n\in \mathbb {Z}^{\prime}}$. The role of the control parameters is examined and the following results have been proven: (i) when $\beta \neq 0$, the set of vibrational modes is asymptotically close to the vertical line on the complex $\nu$-plane given by the equation $\Re \nu = \alpha + (1-k_1k_2)/\beta$; (ii) when $\beta = 0$ and the parameter $K = (1-k_1 k_2)/(k_1+k_2)$ is such that $\left |K\right |\neq 1$ then the following relations are valid: $\Re (\nu _n/n) = O\left (1\right )$ and $\Im (\nu _n/n^2) = O\left (1\right )$ as $\left |n\right |\to \infty$; (iii) when $\beta =0$, $|K| = 1$, and $\alpha = 0$, then the following relations are valid: $\Re (\nu _n/n^2) = O\left (1\right )$ and $\Im (\nu _n/n) = O\left (1\right )$ as $\left |n\right |\to \infty$; (iv) when $\beta =0$, $|K| = 1$, and $\alpha>0$, then the following relations are valid: $\Re (\nu _n/\ln \left |n\right |) = O\left (1\right )$ and $\Im (\nu _n/n^2) = O\left (1\right )$ as $\left |n\right |\to \infty$.

Polar optical vibrational modes in quantum dots

1994 ◽  
Vol 49 (19) ◽  
pp. 13704-13711 ◽  
Author(s):  
E. Roca ◽  
C. Trallero-Giner ◽  
M. Cardona
Keyword(s):  
Quantum Dots ◽  
Vibrational Modes

Coupling of vibrational modes of adsorbates: Application to field-induced shifts for CO and CN on Cu(100)

1987 ◽  
Vol 36 (15) ◽  
pp. 8169-8172 ◽  
Author(s):  
P. S. Bagus ◽  
C. J. Nelin ◽  
K. Hermann ◽  
M. R. Philpott
Keyword(s):  
Vibrational Modes

scholarly journals Phonons in Short-Period GaN/AlN Superlattices: Group-Theoretical Analysis, Ab initio Calculations, and Raman Spectra

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 286
Author(s):  
Valery Davydov ◽  
Evgenii Roginskii ◽  
Yuri Kitaev ◽  
Alexander Smirnov ◽  
Ilya Eliseyev ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Ab Initio Calculations ◽  
Ab Initio ◽  
Raman Spectra ◽  
Density Functional ◽  
Structural Characteristics ◽  
Vibrational Modes ◽  
Phonon Modes ◽  
Short Period ◽  
Group Theoretical Analysis

We report the results of experimental and theoretical studies of phonon modes in GaN/AlN superlattices (SLs) with a period of several atomic layers, grown by submonolayer digital plasma-assisted molecular-beam epitaxy, which have a great potential for use in quantum and stress engineering. Using detailed group-theoretical analysis, the genesis of the SL vibrational modes from the modes of bulk AlN and GaN crystals is established. Ab initio calculations in the framework of the density functional theory, aimed at studying the phonon states, are performed for SLs with both equal and unequal layer thicknesses. The frequencies of the vibrational modes are calculated, and atomic displacement patterns are obtained. Raman spectra are calculated and compared with the experimental ones. The results of the ab initio calculations are in good agreement with the experimental Raman spectra and the results of the group-theoretical analysis. As a result of comprehensive studies, the correlations between the parameters of acoustic and optical phonons and the structure of SLs are obtained. This opens up new possibilities for the analysis of the structural characteristics of short-period GaN/AlN SLs using Raman spectroscopy. The results obtained can be used to optimize the growth technologies aimed to form structurally perfect short-period GaN/AlN SLs.

scholarly journals Quantum dynamics of the ππ*/nπ* decay of the epigenetic nucleobase 1,5-dimethyl-cytosine in the gas phase

2020 ◽  
Vol 22 (45) ◽  
pp. 26525-26535
Author(s):  
Martha Yaghoubi Jouybari ◽  
Yanli Liu ◽  
Roberto Improta ◽  
Fabrizio Santoro
Keyword(s):  
Gas Phase ◽  
Quantum Dynamics ◽  
Vibrational Modes

A partial ultrafast ππ* → nπ* transfer is predicted. Many vibrational modes are activated, but oscillations of bonds and angles are quickly damped.

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