共查询到20条相似文献,搜索用时 31 毫秒
1.
<正>The static electric dipole polarizabilities of the ground state and n≤3 excited states of a lithium atom embedded in a weekly coupled plasma environment are investigated as a function of the plasma screening radium.The plasma screening of the Coulomb interaction is described by the Debye-H(u|¨)ckel potential and the interaction between the valence electron and the atomic core is described by a model potential.The electron energies and wave functions for both the bound and continuum states are calculated by solving the Schrodinger equation numerically using the symplectic integrator.The oscillator strengths,partial-wave,and total static dipole polarizabilities of the ground state and n≤3 excited states of the lithium atom are calculated.Comparison of present results with those of other authors, when available,is made.The results for the 2s ground state demonstrated that the oscillator strengths and the static dipole polarizabilities from np orbitals do not always increase or decrease with the plasma screening effect increasing, unlike that for hydrogen-like ions,especially for 2s→3p transition there is a zero value for both the oscillator strength and the static dipole polarizability for screening length D = 10.3106a0,which is associated with the Cooper minima. 相似文献
2.
Mohammed H. E. Abu-Sei’leek 《原子核物理评论》2011,28(4):416-422
With an oscillator basis, the nuclear Hamiltonian is defined in a no core model space. It consists of an effective nucleon nucleon interaction obtained with Brueckner theory from the Reid soft core interaction, a Coulomb potential, nucleon delta transition potentials, and delta delta interaction terms. By performing spherical Hartree Fock (SHF) calculations with the realistic baryon Hamiltonian, the ground state properties of 40Ca are studied. For an estimate of how the delta degree of freedom is excited, SHF calculations are performed with a radial constraint to compress the nucleus. The delta degree of freedom is gradually populated as the nucleus is compressed. The number of Δ’s is decreased by increasing model space. Large amount of the compressive energy is delivered to create massive Δ in the nucleus. There is a significant reduction in the static compression modulus for RSC static compressions which is reduced by including the Δ excitations. The static compression modulus is decreased significantly by en larging the nucleon model space. The results suggest that inclusion of the delta in the nuclear dynamics could head to a significant softening of the nuclear equation of state. 相似文献
3.
The static and dynamic electric dipole, quadrupole, and octupole polarizabilities of the alkaline-earth atoms (beryllium, magnesium, calcium, strontium, and barium) in the ground state were calculated. The dynamic polarizabilities obtained were used to calculate the van der Waals coefficients C 6, C 8, and C 10 of alkaline-earth metal dimers for the interaction of two like atoms in the ground state. The results are compared with other theoretical and experimental data. 相似文献
4.
Fluorescence quenching of UVITEX‐OB [2,5‐thiophenediylbis(5‐tert‐butyl‐1,3‐benzoxazole)] by aniline in different polar and nonpolar solvents was examined at room temperature by steady‐state fluorescence measurements. Positive deviations from the nonlinear Stern–Volmer plots were observed in most of the solvents indicating the extent of quenching to be large. The quencher concentration dependence data were analyzed using ground‐state complex and sphere of action static quenching models in order to interpret the results. The magnitudes of the quenching rate parameters suggest that a sphere of action static quenching model is expected to describe the data most accurately. Also, the results are suggestive of both static and dynamic quenching processes being responsible for the observed positive deviation in the Stern–Volmer plot. Experimental results are described by an equation derived using the finite sink approximation model, which allows the evaluation of diffusion‐limited interaction and the estimation of encounter distance and mutual diffusion coefficient independently. 相似文献
5.
Jun-chen SU 《理论物理通讯》1991,15(2):229-250
By means of the renormalized Dirac spinor wave function and through. the introduction of an effective interaction operator, the exact ~ethe-saypetere quation for multi-fermion bound states has been reduced to an equivalent Pauli-Schrodinger equation. As a result, the specific form of the latter equation in the static approximation has directly been given as well. In comparison of the effective interaction operator appearing in the Pauli-Schrodinger equation with the corresponding S-matrix, a substantial difference between both interactions acting in the bound state and the scattering state emerges which is important to determine an interaction potential in the bound state. 相似文献
6.
Study of Microwave Multiphoton Transition of Rydberg Potassium Atom by Using B-Spline 总被引:2,自引:0,他引:2
JIN Cheng ZHOU Xiao-Xin ZHAO Song-Feng 《理论物理通讯》2005,44(6):1065-1070
Abstract The B-spline expansion technique and time-dependent two-level approach are applied to study the interaction between the microwave field and potassium atoms in a static electric field. We obtain theoretical multiphoton resonance spectra that can be compared with the experimental data. We also obtain the time evolution of the final state in different microwave fields. 相似文献
7.
JIN Cheng ZHOU Xiao-Xin ZHAO Song-Feng 《理论物理通讯》2005,44(12)
The B-spline expansion technique and time-dependent two-level approach are applied to study the interaction between the microwave field and potassium atoms in a static electric field. We obtain theoretical multiphoton resonance spectra that can be compared with the experimental data. We also obtain the time evolution of the final state in different microwave fields. 相似文献
8.
M.A. Bouchiat C. Bouchiat 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,15(1):5-18
We propose a direct method of detection of the nuclear anapole moment. It is based on the existence of a linear Stark shift
for alkali atoms in their ground state perturbed by a quadrupolar interaction of uniaxial symmetry around a direction and a magnetic field. This shift is characterized by the T-even pseudoscalar (
.
)(∧
.
)/B
2. It involves on the one hand the anisotropy of the hyperfine interaction induced by the quadrupolar interaction and, on the
other, the static electric dipole moment arising from electroweak interactions inside the nucleus. The case of ground state
Cs atoms trapped in a uniaxial (hcp) phase of solid 4He is examined. From an explicit evaluation of both the hyperfine structure anisotropy and the static dipole deduced from
recent empirical data about the Cs nuclear anapole moment, we predict the Stark shift. It is three times the experimental
upper bound to be set on the T-odd Stark shift of free Cs atoms in order to improve the present limit on the electron EDM.
Received 20 December 2000 相似文献
9.
A non Eulerian framework for a renormalized theory of isotropic homogeneous steady state turbulence at high Reynold's numbers is developed. By construction it is invariant under random Galilei transformations. A direct interaction factorization is free of infrared singularities and yields Kolmogorov scaling for the static as well as for the dynamic correlation and response functions. 相似文献
10.
?yvind Geelmuyden Gr?n 《General Relativity and Gravitation》2010,42(6):1375-1379
The investigation of the stability properties of certain variants of Einstein’s static universe performed by Carneiro and
Tavakol (in Stability of the Einstein static universe in the presence of vacuum energy) is generalized. It is shown that all
versions of Einstein’s static universe without interaction between the two fluids it contains are unstable. Interaction between
the fluids may stabilize the universe. The condition for stability by perturbation of the scale factor from its static value
is deduced for a class of universe models containing those investigated by Carneiro and Tavakol. Stability of the static state
requires that energy is transformed to matter during such a perturbation. 相似文献
11.
In this paper, we show that the non-Newtonian gravitational potential can be explained by a scalar-tensor model with torsion in the weak field and static state approximation. The torsional effect is the intermediate-range interaction. 相似文献
12.
The pressure-dependence of the time-integrated perturbation factor of excited41K nuclei slowing down in Ar gas was calculated and compared to our experimental data. The models used were (1) Abragam—Pound
plus static interaction, (2) the Scherer model viewed as a non-stationary sequence of static interaction, and (3) our non-stationary
extension of the Scherer—Blume model. The calculations used detailed and quantitative information on nuclear and atomic parameters
characterizing the perturbation mechanism. A good agreement is attained between experimental data and calculations.
Supported by FINEP and CNPq. 相似文献
13.
14.
15.
S. Pleutin A. Ovchinnikov 《The European Physical Journal B - Condensed Matter and Complex Systems》2001,23(4):521-531
The static polarizability of cylindrical systems is shown to have a strong dependence on a uniform magnetic field applied
parallel to the tube axis. This dependence is demonstrated by performing exact numerical diagonalizations of simple cylinders
(rolled square lattices), armchair and zig-zag carbon nanotubes (rolled honeycomb lattices) for different electron-fillings.
At low temperature, the polarizability as function of the magnetic field has a discontinuous character where plateau-like
region are separated by sudden jumps or peaks. A one to one correspondence is pointed out between each discontinuity of the
polarizability and the magnetic-field induced cross-over between the ground state and the first excited state. Our results
suggest the possibility to use measurements of the static polarizability under magnetic field to get important informations
about excited states of cylindrical systems such as carbon nanotubes.
Received 29 March 2001 and Received in final form 8 August 2001 相似文献
16.
D.J. Andrews 《Journal of Physics and Chemistry of Solids》1973,34(5):825-840
An empirical equation of state that is thermodynamically consistent is found for the alpha (body-centered-cubic) and epsilon (hexagonal-close-packed) phases of iron. It is fit to all available types of experimental data-calorimetic, thermal expansion, acoustic, static compression, and shock data. All thermodynamic identities are satisfied, since expressions for all observables are derived from a thermodynamic potential. No specific theoretical assumptions are made, but the Helmholtz potential is formulated in terms of a number of adjustable functions of single variables by applying some general considerations of lattice vibrations, conduction electrons, and ferromagnetic exchange interaction. The effective Gruneisen parameter depends on temperature as well as volume. Ultrasonic and shock data for the alpha phase are found to be consistent with X-ray determinations of compression based on the sodium chloride standard. The Slater and Dugdale-MacDonald relations are tested against the fit at low pressure and are found to be in error. At high pressure not enough different types of data exist to establish a unique fit without theoretical assumptions. 相似文献
17.
We investigate clean cylindrical nanostructures with an applied
longitudinal static magnetic field. The ground state of these
systems becomes degenerate for particular values of the field due
to Aharonov-Bohm effect. The Coulomb interaction introduces
couplings between the electronic configurations. Consequently,
depending on particular selection rules, the ground state may
become, in the interacting case, a many body state at the
degeneracy points: a gap is then opened. To study this problem,
we propose a variational multireference wave function which goes
beyond the Hartree-Fock approximation. Using this ansatz, in
addition to the replacements of some crossings by avoided
crossings, two other important effects of the electron-electron
interaction are pointed out: (i) the long-range part of the
Coulomb potential tends to shift the position in magnetic field
of the crossing or avoided crossing points and, (ii) at the
points of degeneracy or near degeneracy, the interaction can
drive the system from a singlet to a triplet state inducing new
real crossing points in the ground state energy curve as function
of the field. In any case, the crossing points that are due to
either orbital or spin effects, should manifest themselves in
various experiments as sudden changes in the response of the
system (magnetoconductance, magnetopolarisability, ...) when the
magnetic field is tuned. 相似文献
18.
S. Martin J. Bernard L. Chen A. Denis J. Désesquelles 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):27-32
Resonant excitation or resonant electron scattering is a two step process in which Auger rates are involved in both steps.
First an electron is captured into a bound state and a bound electron is excited (inverse Auger effect). Then an Auger transition
leads to the emission of the electron from the ion. The corresponding cross-sections are very sensitive to the Auger rates
and allow a detailed study of the Breit interaction which is a current-current contribution to the static electron-electron
interaction. The contribution of the Breit interaction to the cross-section of resonant excitation on hydrogen-like uranium
ions is discussed and shown that it is roughly twice as large as in the case of dielectronic recombination.
Received 4 August 1999 and Received in final form 29 September 1999 相似文献
19.
Jerzy Dajka 《Entropy (Basel, Switzerland)》2021,23(6)
Quantum ring accommodating interacting spin-less fermions threaded by magnetic flux with a non-classical component added to a static, inducing persistent current, is considered. It is investigated how current flowing in the ring becomes affected by a state of non-classical flux and how Coulomb interaction between fermions influences entanglement of quantum ring and the driving field. In particular it is shown that in an absence of decoherence and under certain conditions fermion–fermion interaction is necessary for a ring–field entanglement to occur. 相似文献
20.
The wearless friction originating from molecular interactions has been discussed in this paper. We find that the frictional properties are closely related to the structural match of two surfaces in relative motion. For the surfaces with incommensurate structure and week inter-surface interaction, zero static and kinetic friction can be achieved. In a sliding considered as in a quasi-static state, the energy dissipation initiates when interfacial particles move in a discontinuous fashion, which gives rise to a finite kinetic friction. The state of superlubricity is a result of computer simulations, but the prediction will encourage people to look for a technical approach to realizing the state of super low friction. 相似文献