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1.
The composite Anderson-Newns model and triangular weighted density of states are used to study the electron density of states,
magnetic moment and charge transfer of adatoms for a chemisorbed system. The model has been applied to hydrogen chemisorbed
on nickel. It has been observed that with the increase in coverage, number of B-AB states as well as bond strength increases,
whereas the magnetic moment and adatom charge decrease with coverage. These results match with the experimental data. 相似文献
2.
In this paper a variation in density of states (DOS) of the substrate due to chemisorption of hydrogen on transition metals
using composite Anderson-Newns model has been investigated for different coverages in quasi-chemical approximation of Fowler
and Guggenhiem, which in the limitz→∞ gives the Bragg-Williams approximation as a special case. Variation in density of states has been studied for one-dimensional
periodic substrate with change in adatom interaction energy and coverage. With increase in coverage, the bonding and antibonding
(B-AB) peaks are found to shift towards higher energies and at the same time relative height of the peaks also increases.
The interesting feature to observe is that both approximations for a particular coverage, give split-off states with different
height for both (B-AB) peaks. It particularly indicates change in B-AB states, representing amount of chemisorption, with
the change in interaction energy between adatoms. At the same time bond strength is also found to decrease with interaction
between adatoms. 相似文献
3.
Eigensolutions of the Bohr collective Hamiltonian are obtained by expanding its eigenstates on a truncated basis which is adaptable to the most general potential energy and mass parameter surfaces. After a short survey of the method in use, its numerical accuracy is assessed from results obtained in some selected cases. The results of preliminary calculations for154, 156, 158Er and232Th nuclei (where the potential energy surfaces are deduced from self-consistent calculations using the Skyrme SIII force) are also briefly discussed. 相似文献
4.
5.
We construct the exact solution for the quadratic coupling of a scalar field to an external source. With increasing dimension of space-time the perturbation becomes more and more singular, allowing us to verify the various predictions which Glimm has extracted from the perturbation theory of Møller operators. 相似文献
6.
G. Adomian 《Foundations of Physics Letters》1995,8(6):583-587
The decomposition method [1–5] is applied to the Maxwell equations to obtain analytic approximations. 相似文献
7.
Dukelsky J Gueorguiev VG Van Isacker P Dimitrova S Errea B Lerma S 《Physical review letters》2006,96(7):072503
The complete exact solution of the T = 1 neutron-proton pairing Hamiltonian is presented in the context of the SO(5) Richardson-Gaudin model with nondegenerate single-particle levels and including isospin symmetry-breaking terms. The power of the method is illustrated with a numerical calculation for for 64Ge for a pf + g9/2 model space which is out of reach of modern shell-model codes. 相似文献
8.
The exact solution of the proton-neutron isoscalar-isovector (T=0,1) pairing Hamiltonian with nondegenerate single-particle orbits and equal pairing strengths is presented for the first time. The Hamiltonian is a particular case of a family of integrable SO(8) Richardson-Gaudin models. The exact solution of the T=0,1 pairing Hamiltonian is reduced to a problem of 4 sets of coupled nonlinear equations that determine the spectral parameters of the complete set of eigenstates. The microscopic structure of individual eigenstates is analyzed in terms of evolution of the spectral parameters in the complex plane for a system of A=80 nucleons. The spectroscopic trends of the exact solutions are discussed in terms of generalized rotations in isospace. 相似文献
9.
A new compact form of the dynamical equations of relativity is proposed. The new form clarifies the covariance of the equations under coordinate transformations of the space-time. On a deeper level, we obtain new insight into the infinite-dimensional symplectic geometry behind the dynamical equations, the decompositions of gravitational perturbations, and the space of gravitational degrees of freedom. Prospects for these results in studying fields coupled to gravity and the quantization of gravity are outlined.This essay was awarded the second prize for 1976 by the Gravity Research Foundation. 相似文献
10.
Using Scanning Tunneling Microscopy (STM) and ab initio theory we identify a new chemisorbed structure of benzene on Si(100) which we term ‘inter-dimer butterfly,’ ID-BF (C). This involves di-σ-bonding of benzene to two adjacent Si-dimers of a single dimer-row. This configuration is always found in association with a C-type defect, as shown by STM images taken immediately before formation or after elimination of the ID-BF (C) adsorbate. Ab initio calculations yield a binding energy of 2.4 eV for this new structure, higher than the binding energies of other possible chemisorbed configurations of benzene. 相似文献
11.
Qing-ping Liu 《International Journal of Theoretical Physics》1990,29(3):247-251
A spectral problem studied by Roy Chowdhury and Swapna Roy is discussed and the corresponding Hamiltonian structure is obtained. 相似文献
12.
Yu. I. Bobrovnitskii 《Acoustical Physics》2004,50(6):647-650
The method of active impedance matching is applied to the well-known problem of an acoustically transparent body. Two laws of active force control, by velocity and by pressure, are obtained for solving the problem. 相似文献
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15.
A unified presentation of the quasi-exact solutions of the Bohr Hamiltonian with a sextic oscillator potential is offered by evidencing the similarities and the differences between them. An extended study of the Bohr Hamiltonian with sextic potential for γ-rigid triaxial nuclei is conducted, focusing on the evolution of the energy spectra and B(E2) transition probabilities when the order of the quasi-exactly solvable system is increased. The effect is analyzed throughout the shape phase transition from a γ-rigid triaxial vibrator to an anharmonic one and especially in its critical point. The new results are tested by several applications for experimental data, improving the previous calculations and providing new possible triaxial nuclei. 相似文献
16.
Klaus W. Becker Hyekyung Won Peter Fulde 《Zeitschrift für Physik B Condensed Matter》1989,75(3):335-345
A recently developed new form of projection technique is applied to the computation of the ground-state energyE
0 of the antiferromagnetic Heisenberg Hamiltonian on a square lattice, demonstrating its usufulness. The calculations are done analytically and do neither require the use of time-dependent operators nor Wick's theorem. A value ofE
0=–2NJ0.3337 is found whereN is the number of sites in good agreement with series expansions. 相似文献
17.
M. Arminjon 《Annalen der Physik》2011,523(12):1008-1028
In a general spacetime, the possible choices for the field of orthonormal tetrads lead (in standard conditions) to equivalent Dirac equations. However, the Hamiltonian operator is got from rewriting the Dirac equation in a form adapted to a particular reference frame, or class of coordinate systems. That rewriting does not commute with changing the tetrad field (uα ). The data of a reference frame F fixes a four‐velocity field v, and also fixes a rotation‐rate field Ω . It is natural to impose that u0 = v. We show that then the spatial triad (up) can only be rotating w.r.t. F, and that the title problem is solved if one imposes that the corresponding rotation rate Ξ be equal to Ω – or also, if one imposes that Ξ = 0 . We also analyze other proposals which were aimed at solving the problem of the non‐uniqueness of the Dirac Hamiltonian. 相似文献
18.
J. N. Goldberg 《General Relativity and Gravitation》1988,20(9):881-891
The Hamiltonian for general relativity is examined in the strong gravity (SG) limitG . In this limit a perfect fluid moves irrotationally along geodesics. An appropriate SG limit for the scalar field is developed such that the energy density has a limit. The solutions in this limit, which were previously known, are shown to come out simply and directly. A classification of the trace-free part of the momentum is given in the Appendix. 相似文献
19.
The linear response function in the density functional formalism, developed by Ying, Smith and Kohn, is applied to alkali chemisorption on metallic surfaces. The adion is represented by a pseudopotential perturbing the surface. Binding energies, induced dipole moments, and vibrational frequencies at the equilibrium position are first calculated for the alkalis at finite coverage, as well as, in the limit of zero coverage, on a jellium substrate. The theoretical results are in good agreement with available experimental results. The effect of electric fields on chemisorbed alkali ions is discussed with reference to interpretation of experimental results. The crystalline structure is then introduced in the form of a periodic pseudocharge density representing the ionic lattice. In this model, corrections to the quantities calculated in the jellium approximation are obtained for both low index and high index planes. Preferred adsorption sites are determined and found to be consistent with experimental findings. 相似文献
20.
J. Lu 《Il Nuovo Cimento D》1996,18(6):765-770
Summary A new dromion solution is obtained for a (2+1)-dimensional integrable model: the Davey-Stewartson equation. Some interesting
questions which emerge in the procedure of getting the solution are also discussed. 相似文献