共查询到20条相似文献,搜索用时 172 毫秒
1.
F.-Z. Ighezou R.J. Lombard J. Mareš 《The European Physical Journal A - Hadrons and Nuclei》2001,11(1):79-85
We have applied to the 208Pb muonic atom a series of recurrence relations relating the moments of the ground-state density and the energy differences
between the 1s level and the states of the line. The large amount of precise experimental data and the electromagnetic character of the interaction allow a detailed
test of the method for determining the ground-state density and reconstructing the local equivalent potential. Though the
present work is limited to the study of the efficiency for a given trial density, it results in a semi-quantitative analysis
with an accuracy better than 1%.
Received: 18 December 2000 / Accepted: 18 April 2001 相似文献
2.
P. Domokos T. Kiss J. Janszky 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(1):49-53
A beam of diatomic molecules scattered off a standing wave laser mode splits according to the rovibrational quantum state
of the molecules. Our numerical calculation shows that single state resolution can be achieved by properly tuned, monochromatic
light. The proposed scheme allows for selecting non-vibrating and non-rotating molecules from a thermal beam, implementing
a laser Maxwell's demon to prepare a rovibrationally cold molecular ensemble.
Received 23 August 2000 and Received in final form 17 November 2000 相似文献
3.
P.L. Christiansen Y.B. Gaididei F.G. Mertens S.F. Mingaleev 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,19(4):545-553
We investigate the properties of nonlinear excitations in different types of soliton carrying systems with long-range dispersive interactions. We show that length-scale competition in such systems, universally results in a multi-component structure of nonlinear excitations
which may lead to a new type of multistability: coexistence of different nonlinear excitations at the same value of the spectral parameter (i.e., velocity in the case of anharmonic lattices or frequency in nonlinear Schr?dinger models).
Received 31 August 2000 and Received in final form 14 December 2000 相似文献
4.
B. Rohwedder 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):255-260
Fringe shapes in a multiple-beam de Broglie-wave interferometer based on the atomic Kapitza-Dirac effect are studied. An all-optical
implementation of such a device is proposed. A realization in the time-domain, using Bose-Einstein condensates released from
a trap, seems viable within the present state of the art.
Received 5 April 2000 and Received in final form 14 July 2000 相似文献
5.
S. Varga K. Bolton H. Grönbeck A. Snis A. Rosén B. Fricke 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,16(1):29-32
We present recent theoretical results for the V3 and Au4 clusters. Calculations of the V3 doublet system indicate that the 6-311+G(d) basis set is sufficiently flexible to provide reliable minimum energy structures
and vibrational frequencies, that these structures and frequencies are insensitive to spin contamination of the wave function
when the BPW91 functional is used, and that changing to the B3LYP functional may result in very different structures and frequencies.
A computationally less expensive scalar relativistic treatment of Au4 clusters gives structural properties that are in good agreement with those obtained using a four-component method.
Received 30 November 2000 相似文献
6.
J. Dabrowski J. Rożynek G.S. Anagnostatos 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):125-131
It is shown that among four models of the Nijmegen baryon-baryon interaction only model F --which leads to a repulsive potential
felt by the Σ hyperon inside the nucleus-- is consistent both with the analysis of Σ- atoms and of the (K
-,π) reactions. The Nijmegen models are used to determine the strong complex single-particle (s.p.) potential of Σ-, and to calculate the strong-interaction shifts and widths of the lowest observed levels of Σ- atoms. The results obtained with model F are in best agreement with the experimental data.
Received: 15 January 2002 / Accepted: 14 March 2002 相似文献
7.
V.I. Yukalov 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,20(4):609-617
A novel approach to analyzing time series generated by complex systems, such as markets, is presented. The basic idea of the
approach is the Law of Self-Similar Evolution, according to which any complex system develops self-similarly. There always exist some internal laws governing the evolution
of a system, say of a market, so that each of such systems possesses its own character regulating its behaviour. The problem
is how to discover these hidden internal laws defining the system character. This problem can be solved by employing the self-similar approximation theory, which supplies the mathematical foundation for the law of self-similar evolution. In this report, the theoretical basis
of the new approach to analyzing time series is formulated, with an accurate explanation of its principal points.
Received 15 August 2000 相似文献
8.
C.M. Dion A. Keller O. Atabek 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(2):249-255
Using a rigid-rotor model, we study the orientation dynamics of polar diatomic molecules excited by experimentally available
half-cycle pulses. The results of the numerical solution of the time-dependent Schr?dinger equation are compared to those
of an approximate “sudden-impact” impulsive model neglecting the molecular rotation during the pulse. We show that efficient
orientation is achieved during time periods of several picoseconds for LiCl. For short pulses, where the kicked molecule model
is valid, orientation turns out to be mainly sensitive to the time-integrated field amplitude and not the shape or rise time
of the pulse.
Received 16 August 2000 and Received in final form 4 December 2000 相似文献
9.
Z.-C. Yan 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,18(1):15-18
The fully correlated calculations of the Zeeman gJ factors for the first three quartet S states of lithium are presented, including relativistic and radiative corrections of
orders α2, α2
m/M, and α3. The isotope shifts in gJ are predicted precisely for various isotopes of lithium.
Received 4 December 2000 and Received in final form 26 September 2001 相似文献
10.
Recent experimental data obtained by the OBELIX collaboration on ˉpD and ˉp4 He total annihilation cross sections are analyzed. The combined analysis of these data with existing antiprotonic atom data
allows, for the first time, the imaginary parts of the S-wave scattering lengths for the two nuclei to be extracted.
The obtained values are: Im asc
0= [−0.62 ± 0.02 stat) ± 0.04 (sys)] fm for ˉpD and Im asc
0= [−0.36 ± 0.03 (stat)+0.19
−0.11 (sys)] fm for ˉp 4He. This analysis indicates an unexpected behaviour of the imaginary part of the ˉp-nucleus S-wave scattering length as a
function of the atomic weight A:
|Im asc
0| (macr;pp) > |Im asc
0| (ˉpD) > |Im asc
0 (ˉp4 He).
Received: 3 November 1999 / Revised version: 15 December 1999 相似文献
11.
T.S. Jensen V.E. Markushin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(2):165-181
The differential and total cross-sections for the scattering of muonic, pionic, kaonic and antiprotonic hydrogen in excited
states from atomic hydrogen have been calculated for the purpose of atomic cascade calculations. The scattering problem is
treated in a fully quantum mechanical framework which takes the energy shifts and, in the case of the hadronic atoms, the
widths of the ns states into account. The validity of semiclassical approximations is critically examined.
Received 4 December 2001 and Received in final form 4 February 2002 相似文献
12.
S. Evangelisti 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,20(1):61-69
The expansion structure of a CI vector as combination of excitations from a model-space reference determinant is investigated.
It is shown that between the linear and the exponential expansions there is a relation which is similar to the single-reference
case, if the internal excitations are adsorbed into the reference vector. Moreover, expansions with respect to different determinants
are related by a set of linear equations. By using these two properties, a State-Specific Coupled-Cluster formalism is proposed.
Received 2 November 2000 / Received in final form 1st March 2002 Published online 28 June 2002 相似文献
13.
J.M. Polson I. Vattulainen H. Zhu M.J. Zuckermann 《The European physical journal. E, Soft matter》2001,5(4):485-497
We employ off-lattice Monte Carlo simulations to study lateral diffusion in lipid-sterol bilayers using a two-dimensional
model system which has been designed to simulate the experimental phase diagrams of both lipid-cholesterol and lipid-lanosterol
systems. We focus on the effects of varying sterol concentration and temperature on the tracer diffusion coefficient, D, which characterizes the lateral motion of single tagged lipids in a bilayer. Generally, we find that increasing the cholesterol
concentration suppresses D due to an increased conformational ordering of lipid chains. We argue that this effect competes with an increase in the average
free area per lipid, which favours an increase in D. At temperatures close to the main transition temperature, the competition between the two effects leads to intriguing behavior
of D. Overall, the model results are in excellent qualitative agreement with available experimental results for lipid-cholesterol
mixtures. Additional studies of a model lipid-lanosterol system, for which experimental diffusion results are not available,
predict that the presence of lanosterol has a smaller effect than cholesterol on reducing D relative to the pure lipid system. We conclude that the molecular model employed contains the essential features required
to describe many of the qualitative features of the lateral diffusion behavior in lipid-sterol systems.
Received 24 November 2000 and Received in final form 30 April 2001 相似文献
14.
T.S. Jensen V.E. Markushin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,21(3):261-270
The deexcitation of exotic hydrogen atoms in highly excited states in collisions with hydrogen molecules has been studied
using the classical-trajectory Monte Carlo method. The Coulomb transitions with large change of principal quantum number n have been found to be the dominant collisional deexcitation mechanism at high n. The molecular structure of the hydrogen target is shown to be essential for the dominance of transitions with large Δn. The external Auger effect has been studied in the eikonal approximation. The resulting partial wave cross-sections are consistent
with unitarity and provide a more reliable input for cascade calculations than the previously used Born approximation.
Received 28 May 2002 Published online 15 October 2002
RID="a"
ID="a"e-mail: thomas@physik.unizh.ch 相似文献
15.
A.K. Das M. Ehara H. Nakatsuji 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(2):195-200
Excited states of the s, p, and d symmetries up to principal quantum number n = 4 are studied for the first eight members of Ne isoelectronic sequence (Ne to Cl7+) by the SAC-CI (symmetry-adapted-cluster configuration-interaction) method. The valence STO basis sets of Clementi et al. and the optimized excited STO are used by the STO-6G expansion method. The calculated transition energies agree well with
the experimental values wherever available.
Received 26 July 2000 and Received in final form 14 September 2000 相似文献
16.
Single-beam optical bottle for cold atoms using a conical lens 总被引:2,自引:0,他引:2
L. Cacciapuoti M. de Angelis G. Pierattini G.M. Tino 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,14(3):373-376
We report a new method to generate an optical dipole potential with a null intensity region surrounded in all directions by
light walls. This is achieved with a simple scheme based on a conical lens. Applications to optical trapping of neutral atoms
are discussed.
Received 4 September 2000 and Received in final form 21 January 2001 相似文献
17.
F.X. Gadéa T. Leininger A.S. Dickinson 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(2):251-255
An improved ab initio calculation has been performed for the potential for the LiH a 3Σ+ state, using two very large basis sets. The Basis Set Superposition Error (BSSE) correction has been determined for both
basis sets and the non-Born-Oppenheimer correction estimated to be negligible. The best potential is approximately 10% deeper
than the previous estimate. Vibrational energies and scattering lengths have been calculated for 6,7LiH(D) with both potentials, with and without the BSSE correction, and also with an estimated potential expected to bracket
the true potential. The 7LiH scattering length is estimated to be (45 ± 4)a0 and hence the low-energy cross-section in the best a 3Σ+ potential is about half that calculated previously. Enhanced cooling by 7Li of trapped H atoms remains feasible.
Received 30 April 2001 相似文献
18.
B. Ketzer T. von Egidy F.J. Hartmann C. Maierl R. Pohl J. Eades E. Widmann T. Yamazaki M. Kumakura N. Morita R.S. Hayano M. Hori T. Ishikawa H.A. Torii I. Sugai D. Horváth 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,13(3):305-316
The quenching of metastable states of antiprotonic helium by collisions with hydrogen and deuterium molecules was studied.
A systematic investigation of the delayed annihilation time spectra at various H2 and D2 admixture ratios at the ppm level revealed characteristic changes of their shape, which indicated a strong principal and
orbital quantum number dependent quenching of levels in both cases. Applying a laser spectroscopy technique to measure the
lifetimes of individual states and cascades we deduced H2 and D2 quenching cross-sections for the states (n, l )= (39, 35) and (37, 34). These cross-sections establish for D2 molecules the strong increase of the quenching efficiency with increasing principal quantum number n of the state under investigation previously reported for the case of H2 admixtures. Our experiments indicate that the low-n state (37, 34) is somewhat less affected by D2 than by H2, while the high-n state (39, 35) is equally quenched by both isotopes.
Received 2 October 2000 相似文献
19.
An atom faucet 总被引:3,自引:0,他引:3
W. Wohlleben F. Chevy K. Madison J. Dalibard 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(2):237-244
We present a simple and efficient source of slow atoms. From a background vapour loaded magneto-optical trap (MOT), a thin
laser beam extracts a continuous jet of cold rubidium atoms. The jet that is typical to leaking MOT systems is created without
any optical parts placed inside the vacuum chamber. We also present a simple three dimensional numerical simulation of the
atomic motion in the presence of these multiple saturating laser fields combined with the inhomogeneous magnetic field of
the MOT. At a pressure of P
Rb87 = 10-8 mbar and with a moderate laser power of 10 mW per beam, we generate a flux Φ = 1.3×108 atoms/s with a mean velocity of 14 m/s and a divergence of 10 mrad.
Received 13 January 2001 相似文献
20.
D. O. Odero 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(1):3-8
The time-dependent treatment of positron-hydrogen scattering for a zero total angular momentum has been presented. The initial
wavefunction of the positron-hydrogen scattering system has been expanded in terms of three dimensional dynamical wave functions
to include all higher angular momenta by solving a set of three coupled differential equations. This wavefunction is then
time evolved using Taylor series expansion of the evolution operator. The excitation probabilities are monitored as the wavefunction
propagates until there is no more change in the probabilities. The positron impact excitation cross-sections extracted from
the final wavefunction are compared with the available results of converged close coupling approach.
Received 23 July 2001 and Received in final form 25 November 2001 相似文献