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1.
Molecular auxiliary functions A
n
(p) and B
n
(pt), arising in the Hartree-Fock-Roothaan (HFR) approximation for molecules, Ewald’s crystal lattice theory, electromagnetic
stopping theory, and other approximate methods, are evaluated and analysed in the range of 17≤n≤60 and 25≤pt≤60. 相似文献
2.
By means of a transfer matrix method, we show that the residual entropy S of the two-dimensional square lattice antiferromagnetic Ising model in the maximal critical field satisfies (ln λ
n
)/(n+1)≤S≤(ln λ
n
)/n, where λ
n
is the largest eigenvalue of the transfer matrix F
n
on a strip of width n. Using these bounds, we numerically calculate the value of S, with precise estimates on the errors, namely, S=0.394198±0.020747. 相似文献
3.
Frank E. Harris 《Pramana》2003,61(4):C779-C780
Guseinov, Mamedov, Kara and Orbay (Pramana - J. Phys.
56, 691 (2001)) propose methods for evaluating the molecular auxiliary functionsA
n(p) andB
n(pt) for the range 17 ≤n ≤ 60 and 25 ≤pt ≤ 60. However, their procedure forA
n(p) is not new, and that forB
n(pt) is less efficient for their target range than another well-known method. Their approach does have merit for smaller non-zero
values ofpt. Two minor errors in table 1 of their paper are also identified. 相似文献
4.
R. Brazis L. Safonova R. Narkowicz 《International Journal of Infrared and Millimeter Waves》1997,18(8):1575-1584
Non-transmission bands of electromagnetic waves propagating along the layers in periodic structures are studied in the steady
magnetic field perpendicular both to the uniaxis and the direction of propagation. The band control range (36÷75 GHz) inn-InSb/Al2O3 structures with the carrier densities 4 1013 ≤n ≤ 8 1014 cm−3 in magnetic fieldsB
o ≤ 2 T at temperatures 77 ≤T ≤ 200 K is found to agree with the calculated in the effective medium approximation. Attenuation down to −50 dB within the
band is observed. The band lineshape is found to indicate additional effects related to the finite layer thickness and periodicity
termination predicted by a more rigorous theory of dispersion. 相似文献
5.
The experimental nuclear level density below the neutron binding energy B
n
in the mass region 40 ≤ A ≤ 200 is approximated to a high precision on the basis of the Strutinsky model combined with the assumption that the coefficient
of collective enhancement of the level density for a given number of excited quasiparticles decreases exponentially with increasing
excitation energy. This combination of model concepts makes it possible to reproduce faithfully not only the general trend
revealed by the method developed at the Joint Institute for Nuclear Research (JINR, Dubna) in the change in the level density
with increasing excitation energy in any nuclei but also the fine structure of this level density. Realistic experimental
information about the change in the relationship between the densities of quasiparticle- and vibrational-type states was obtained
for the first time for any nuclei virtually up to the neutron binding energy B
n
. 相似文献
6.
By means of a transfer matrix method, we show that the residual entropy S of the two dimensional square lattice Blume-Emery-Griffiths model on the antiquadrupolar-disordered and ferromagnetic-antiquadrupolar-disordered
phase boundaries satisfies the inequalities (ln λ
1,n
)/(n+1)≤S≤(ln λ
1,n
)/n, where λ
1,n
is the largest eigenvalue of a transfer matrix F
n
on a strip of width n. These bounds imply the existence of a O(1/n) correction in the approximation of S by (ln λ
1,n
)/n. Using these bounds, we calculate numerically the value of S, with precise estimates on the errors. 相似文献
7.
Timothy M. Garoni Giovanni Ossola Marco Polin Alan D. Sokal 《Journal of statistical physics》2011,144(3):459-518
We study, via Monte Carlo simulation, the dynamic critical behavior of the Chayes–Machta dynamics for the Fortuin–Kasteleyn
random-cluster model, which generalizes the Swendsen–Wang dynamics for the q-state Potts ferromagnet to non-integer q≥1. We consider spatial dimension d=2 and 1.25≤q≤4 in steps of 0.25, on lattices up to 10242, and obtain estimates for the dynamic critical exponent z
CM. We present evidence that when 1≤q≲1.95 the Ossola–Sokal conjecture z
CM≥β/ν is violated, though we also present plausible fits compatible with this conjecture. We show that the Li–Sokal bound z
CM≥α/ν is close to being sharp over the entire range 1≤q≤4, but is probably non-sharp by a power. As a byproduct of our work, we also obtain evidence concerning the corrections to
scaling in static observables. 相似文献
8.
We investigate quantum dynamics of vibrational excitations in one-dimensional (1D) molecular chain. Our model includes nearest
neighbor interaction between identical molecular sites and one impurity atom placed in the middle (n = 0). We show that upon exciting the impurity site, its excess energy for relatively long for molecular scales time up to
100 ps is not redistributed uniformly among all other degrees of freedom. On the contrary an excitation propagates along the
chain, reflected from the chain ends, and quantum interference of these waves yields to recurrence cycles and echo phenomena.
For a critical cycle number k
c
, echo components of the neighboring cycles start to overlap, and eventually for k ≫ k
c
dynamics looks like chaotic one. The critical cycle number k
c
depends on the coupling strength 0 ≤ C ≤ 1 of the impurity site with its neighbors n = ±1. k
c
achieves the maximum for C
2 = 1/2. Our results are in qualitative agreement with experimental data on vibrational excitations in various (CH2)
n
molecular chains, and besides offer a way for loss-free energy transfer between separated in space reaction centers. 相似文献
9.
V. I. Inozemtsev 《Czechoslovak Journal of Physics》2000,50(11):1251-1256
For some one-parameter setH
N of linear combinations ofN(N−1)/2 elementary transpositions {P
jk} (1≤j<k≤N) at arbitrary naturalN≥3 one can construct a variety {I
m} (3≤m≤N) of operators which commute withH
N. Being applied toSU(n) spin representations of the permutation group, this proves the integrability of 1D periodic spin chains with elliptic short-range
interaction.
Presented at the 9th Colloquium “Quantum Groups and Integrable Systems”, Prague, 22–24 June 2000. 相似文献
10.
The electrochemical intercalation of Li+ into hafnium-doped TiS2 was studied using time-differential perturbed angular correlations (TDPAC). The181Ta nuclear quadrupole interaction was monitored as a function of the charge transfer,n
F. For low uptakes, 0≤n
F≤0.03, a two-phase region was found with an empty host interaction, characterized byV
q=458(4) MHz, η=0.19(3) and δ-0.083(5), and a second interaction corresponding to lithiated material withv
q=597(5) MHz, η=0.13(4) and δ=0.061(5). No evidence was found for intermediate phases. 相似文献
11.
Summary Crystallization kinetics is studied in glassy Ge22Se78−x
Bi
x
(0≤x≤10) using isothermal annealing at various temperatures between the glass transition and melting. D.c. conductivity is taken
as a parameter to estimate the extent of crystallization (α). The activation energy of crystallization (ΔE) and the order parameter (n) are calculated by fitting the values of α in Avrami’s equations of isothermal transformation. The results indicate that
ΔE is highly composition dependent and decreases as the Bi concentration increases. 相似文献
12.
S. M. Frolov N. M. Kuznetsov C. Krueger 《Russian Journal of Physical Chemistry B, Focus on Physics》2009,3(8):1191-1252
The objective of the research outlined in this paper was to develop the analytical approximations for calculating real-gas
properties (p-v-T data, thermodynamic functions: internal energy, enthalpy, and entropy, and specific heats) of vapor-phase n-alkanes from C1 (methane) to C14 (normal tetradecane), O2, N2, H2O, CO, CO2, and H2 within the range of pressure 0.05 MPa ≤ p ≤ 20 MPa and temperature 280 K ≤ T ≤ 3000 K aimed for implementation into computational fluid dynamics (CFD)-codes simulating the operation process in modern
Diesel engines. The analytical approximations have been developed based on available literature data and on the new equation
of state for moderately dense gases. The approximations reported are rather simple and therefore can be used directly in CFD
codes. Approximations for mixing rules are also provided. 相似文献
13.
A. D. Smirnov 《Optics and Spectroscopy》2010,109(5):680-686
Vibrational, rotational, and centrifugal spectroscopic constants and radiative parameters, i.e., the Einstein coefficients,
oscillator strengths, and wave numbers for vibrational transitions in electronic systems of bands A
1Σ
u
+-X
1Σ
g
+ (0 ≤ v′ ≤ 25; 0 ≤ v″ ≤ 44), B
1Π
u
-X
1Σ
g
+ (0 ≤ v′ ≤ 29; 0 ≤ v″ ≤ 47), and the radiative lifetimes for the vibrational levels of excited states of the sodium dimer,
are calculated. The calculations are carried out based on semiempirical potential curves constructed in this study. The calculated
spectroscopic constants and radiative lifetimes are compared to the experimental values. 相似文献
14.
The exciton absorption spectra of thin films of (Cs1 − x
Rb
x
)2CdI4 solid solutions have been investigated and the refractive index n(λ) in their transparency window in the concentration range of 0 ≤ x ≤ 1 has been measured. The exciton-band parameters and optical permittivity ɛ∞(x) have been found to linearly depend on the concentration. It is established that excitons are incorporated into the CdI2 sublattice of the solid solutions and belong to intermediate-coupling ones. The characteristics of excitons in ferroelastics
are compared with the corresponding parameters for CdI2, RbI, and CsI, which are used as components to synthesize ternary compounds. 相似文献
15.
Oded Schramm Scott Sheffield David B. Wilson 《Communications in Mathematical Physics》2009,288(1):43-53
The conformal loop ensembles CLE
κ
, defined for 8/3 ≤ κ ≤ 8, are random collections of loops in a planar domain which are conjectured scaling limits of the O(n) loop models. We calculate the distribution of the conformal radii of the nested loops surrounding a deterministic point.
Our results agree with predictions made by Cardy and Ziff and by Kenyon and Wilson for the O(n) model. We also compute the expectation dimension of the CLE
κ
gasket, which consists of points not surrounded by any loop, to be
, which agrees with the fractal dimension given by Duplantier for the O(n) model gasket.
Partially supported by NSF grant DMS0403182. 相似文献
16.
Given a finite set B (basin) with n>1 elements, which we call points, and a map M:B→B, we call such pairs (B,M) monads. Here we study a class of random monads, where the values of M(⋅) are independently distributed in B as follows: for all a,b∈B the probability of M(a)=a is s and the probability of M(a)=b, where a≠b, is (1−s)/(n−1). Here s is a parameter, 0≤s≤1. We fix a point ⊙∈B and consider the sequence M t (⊙), t=0,1,2,… . A point is called visited if it coincides with at least one term of this sequence. A visited point is called recurrent if it appears in this sequence at least twice; if a visited point appears in this sequence only once, it is called transient. We denote by Vis n , Rec n and Tra n the numbers of visited, recurrent and transient points respectively. We prove that, when n tends to infinity, Vis n and Tra n converge in law to geometric distributions and Rec n converges in law to a distribution concentrated at its lowest value, which is one. Now about moments. The case s=1 is trivial, so let 0≤s<1. For any natural number k there is a number such that the k-th moments of Vis n , Rec n and Tra n do not exceed this number for all n. About Vis n : for any natural k the k-th moment of Vis n is an increasing function of n. So it has a limit when n→∞ and for all n it is less than this limit. About Rec n : for any k the k-th moment of Rec n tends to one when n tends to infinity. About Tra n : for any k the k-th moment of Tra n has a limit when n tends to infinity. 相似文献
17.
Hydrogen diffusion in the ordered hydride β-V2H is mainly brought about by a minority fraction of interstitial atoms on antistructural sites. Recently, this mechanism was
elucidated in a single crystal QNS study at temperatures close to the critical point (390 K≤T≤440 K) where already an appreciable amount of antistructural sites is occupied. Here we use the positive muon as a radioactive
hydrogen tracer in order to show that the same diffusion mechanism is also valid at low temperatures (80 K≤T≤320 K) where the different jump processes are very slow and where the fraction of antistructural atoms is tiny but nevertheless
dominates the long range diffusion. 相似文献
18.
B. B. Krichevtsov R. V. Pisarev A. A. Rzhevskii V. N. Gridnev H. -J. Weber 《JETP Letters》1998,67(8):602-606
Spectral measurements of the Voigt birefringence Δn were performed for the cubic magnetic semiconductor Cd1−x
Mn
x
Te (0≤x≤0.52) in order to investigate how the exchange interaction of Mn2+ ions with itinerant electrons depends on the electron wave vector. It was determined that Δn/x
2 is independent of x and the magnetic field direction, i.e., the effect is due to the Mn2+ ions and is isotropic. Below the band gap edge the dispersion of the birefringence Δn can be described well in all samples by the unusual dependence Δn∼(E
g
−ℏω) −3.5. This can be explained by a decrease of the exchange interaction of Mn2+ ions with itinerant electrons with increasing distance from the center of the Brillouin zone.
Pis’ma Zh. éksp. Teor. Fiz. 67, No. 8, 569–573 (25 April 1998) 相似文献
19.
The dependences of the electrical resistivity ρ and the Hall coefficient R on the magnetic field have been measured for single-crystal samples of the n-Bi0.93Sb0.07 semiconductor alloys with electron concentrations in the range 1 × 1016 cm−3 < n < 2 × 1018 cm−3. It has been found that the measured dependences exhibit Shubnikov-de Haas quantum oscillations. The magnetic fields corresponding
to the maxima of the quantum oscillations of the electrical resistivity are in good agreement with the calculated values of
the magnetic fields in which the Landau quantum level with the number N intersects the Fermi level. The quantum oscillations of the Hall coefficient with small numbers are characterized by a significant
spin splitting. In a magnetic field directed along the trigonal axis, the quantum oscillations of the resistivity ρ and the
Hall coefficient R are associated with electrons of the three-valley semiconductor and are in phase with the magnetic field. In the case of
a magnetic field directed parallel to the binary axis, the quantum oscillations associated both with electrons of the secondary
ellipsoids in weaker magnetic fields and with electrons of the main ellipsoid in strong magnetic fields (after the overflow
of electrons from the secondary ellipsoids to the main ellipsoid) are also in phase. In magnetic fields of the quantum limit
ħω
c
/2 ≥ E
F, the electrical conductivity increases with an increase in the magnetic field: σ22(H) ∼ H
k
. A theoretical evaluation of the exponent in this expression for a nonparabolic semiconductor leads to values of k close to the experimental values in the range 4 ≤ k ≤ 4.6, which were obtained for samples of the semiconductor alloys with different electron concentrations. A further increase
in the magnetic field results in a decrease of the exponent k and in the transition to the inequality σ22(H) ≤ σ21(H). 相似文献
20.
The four-dimensional Ising model is simulated on the Creutz cellular automaton using finite-size lattices with linear dimension
4≤L≤8. The exponents in the finite-size scaling relations for the order parameter and the magnetic susceptibility at the finite-lattice
critical temperature are computed to be β=0.49(7), β=0.49(5), β=0.50(1) and γ=1.04(4), γ=1.03(4), γ=1.02(4) for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the
obtained results are consistent with the renormalization group predictions of β=0.5 and γ=1. The values for the critical temperature of the infinite lattice T
c
(∞)=6.6788(65), T
c
(∞)=6.6798(69), T
c
(∞)=6.6802(70) are obtained from the straight-line fit of the magnetic susceptibility maxima using 4≤L≤8 for 7, 14, and 21 independent simulations, respectively. As the number of independent simulations increases, the obtained
results are in very good agreement with the series expansion results of T
c
(∞)=6.6817(15), T
c
(∞)=6.6802(2), the dynamic Monte Carlo result of T
c
(∞)=6.6803(1), the cluster Monte Carlo result of T
c
(∞)=6.680(1) and the Monte Carlo using Metropolis and Wolff-cluster algorithm result of T
c
(∞)=6.6802632±5×10−5. 相似文献