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51.
Q.-H Chen Y.-H. Ren Z.-K Jiao 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,3(3):307-313
The general properties of one-dimensional large Fr?hlich polarons in motion are investigated with the previous extended coherent
states where two-phonon correlations are considered. As a result, the polaron energy, velocity, effective mass, and average
number of virtual phonons as a function the polaron total momentum are evaluated in a wide range of the coupling constant.
In addition, rich information about virtual phonons emitted by the electron in motion is obtained. More importantly, some
intrinsic features of 1D moving polarons are presented for the first time, which may also be suited to moving polarons in
more than one dimensions.
Received: 23 October 1997 / Revised and Accepted: 27 January 1998 相似文献
52.
X. Lü J.H. Chu 《The European Physical Journal B - Condensed Matter and Complex Systems》2002,26(3):375-378
Thermal conductivity of silicon and porous silicon nanowires based on the equation of phonon radiative transport is theoretically
evaluated. The thermal conductivities of silicon nanowires with square cross-sections are found to match molecular dynamics
simulation results reasonably well. It is shown that the results of meso-porous silicon nanowires are about two orders of
magnitude lower than that of silicon nanowires in a wide range of temperature (50 K-300 K).
Received 24 April 2001 and Received in final form 23 December 2001 相似文献
53.
Alexander Q. Wu 《Applied Surface Science》2007,253(15):6301-6304
Ultrafast time-resolved reflectivity of a bismuth thin film evaporated on a silicon substrate is measured to investigate coherent phonons in bismuth. The reflectivity result is analyzed by a linear chirp approximation to obtain the time dependent frequencies of coherent phonons. Not only the optical modes are detected, which are generated by a combination of impulsive stimulated Raman scattering and displacive excitation of coherent phonon, acoustic phonon modes are also observed, which are emitted by the A1g optical phonon. 相似文献
54.
H. Yamada E. B. Starikov D. Hennig 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,59(2):185-192
We numerically investigate quantum diffusion of an electron in a
model of poly(dG)-poly(dC) and poly(dA)-poly(dT) DNA
polymers with fluctuation of the parameters due to the impact of colored noise.
The randomness is introduced by fluctuations of distance between two consecutive bases
along the stacked base pairs.
We demonstrate that in the model the decay time of the correlation can control the spread of the
electronic wavepacket.
Furthermore it is shown that in a motional narrowing regime the averaging over fluctuation
causes ballistic propagation of the wavepacket,
and in the adiabatic regime the electronic states are affected by localization. 相似文献
55.
A two-dimensional tilted axis cranking Hartree-Fock-Bogoliubov (CHFB) calculation is performed for 76Kr and 78Kr nuclei up to high spins J = 30 employing a pairing-plus-quadrupole (PPQ) model interaction Hamiltonian. Intricate details of the evolution of single
particle structures and shapes as a function of spin have been investigated. The results show the existence of energy levels
with high K quantum numbers lying close to the yrast line in both the nuclei. Such high K states should exhibit isomeric characteristics due to the K-selection rules for the γ-decays. Moreover, in 78Kr a new band with J = 20–30 lying below the observed ground band is predicted.
相似文献
56.
This paper reports on the experimental observation of the displacement of a surface plasmon resonance (SPR) excited by a metallic diffraction grating. This effect is achieved by the use of an electro-optical material composed of nano-sized droplets of liquid crystals dispersed in a host polymer. The average refractive index of this material in the form of a thin film on the undulated metal surface can be modified with the application of an external electric field and to tune the wavelength at which the SPR excitation leads to a reflection minimum. The theoretical design and experimental demonstration of the principle of this component are described. 相似文献
57.
Jeffrey J. Field Thomas A. Planchon Wafa Amir Charles G. Durfee Jeff A. Squier 《Optics Communications》2007,278(2):368-376
We demonstrate pulse shaping via arbitrary phase modulation with a reflective, 1 × 4096 element, liquid crystal spatial light modulator (SLM). The unique construction of this device provides a very high efficiency when the device is used for phase modulation only in a prism based pulse shaper, namely 85%. We also present a single shot characterization of the SLM in the spatial domain and a single shot characterization of the pulse shaper in the spectral domain. These characterization methods provide a detailed picture of how the SLM modifies the spectral phase of an ultrashort pulse. 相似文献
58.
B. Ramstein C. Mosbacher T. Hennino W. Augustyniak D. Bachelier H.G. Bohlen J.L. Boyard R. Dahl C. Ellegaard C. Gaarde J. Gosset J.C. Jourdain J.S. Larsen M.C. Lemaire D. L'Hôte H.P. Morsch M. Österlund J. Poitou P. Radvanyi M. Roy-Stephan T. Sams M. Skousen S. Tarlé-Rousteau P. Zupranski 《The European Physical Journal A - Hadrons and Nuclei》2003,16(4):583-597
The exclusive 2H( 3He, t)2p reaction has been studied at 2 GeV for energy transfers up to 500 MeV and triton angles up to 3.4°. The protons were measured in the large acceptance magnetic detector DIOGENE, in coincidence with the forward tritons detected
in a dedicated magnetic arm. The energy transfer spectra extend well above the pion threshold. However, in the region of Δ
excitation, the yield is less than 10% of the inclusive 2H( 3He, t) cross-section, which indicates the small contribution of the ΔN ↦ NN process. The angular distributions of the two
protons in their center of mass have been analysed as a function of energy transfer and triton angle and a Legendre polynomial
decomposition has been achieved. These data have been compared to a model based on a coupled-channel approach for describing
the NN and NΔ systems.
Received: 21 October 2002 / Accepted: 15 November 2002 / Published online: 11 March 2003
RID="a"
ID="a"e-mail: ramstein@ipno.in2p3.fr
RID="†"
ID="†"Deceased.
RID="†"
ID="†"Deceased.
RID="d"
ID="d"Present adress: School of Engineering, J?nk?ping University, P.O. Box 1026, S-551 11 J?nk?ping, Sweden.
Communicated by M. Gar?on 相似文献
59.
Yamada H Starikov EB Hennig D Archilla JF 《The European physical journal. E, Soft matter》2005,17(2):149-154
We numerically investigate localization properties of electronic states in a static model of poly(dG)-poly(dC) and poly(dA)-poly(dT) DNA polymers with realistic parameters obtained by quantum-chemical calculation. The randomness in the on-site energies caused by the electron-phonon coupling is completely correlated to the off-diagonal parts. In the single electron model, the effect of the hydrogen-bond stretchings, the twist angles between the base pairs and the finite system size effects on the energy dependence of the localization length and on the Lyapunov exponent are given. The localization length is reduced by the influence of the fluctuations in the hydrogen bond stretchings. It is also shown that the helical twist angle affects the localization length in the poly(dG)-poly(dC) DNA polymer more strongly than in the poly(dA)-poly(dT) one. Furthermore, we show resonance structures in the energy dependence of the localization length when the system size is relatively small. 相似文献
60.
I. Compagnon R. Antoine D. Rayane Ph. Dugourd M. Broyer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):365-368
Gas phase Ti-C60 clusters are studied by molecular beam electric deflection. The permanent dipole moment of the TiC60 molecule is determined. It is equal to 8.1±1.5
D. This dipole is due to a transfer of electron from the transition metal atom to the C60 cage. No dipole is observed for Ti(C60)2 molecules. This is in agreement with the symmetrical dumbbell-like structure that has been previously proposed.
Received 22 November 2000 相似文献