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Vol. 42, No. 2 (1993)

1993-01-20
CONTENT
1993, 42 (2): 170-172. doi: 10.7498/aps.42.170
Abstract +
GENERAL
EXACT SOLUTION OF SCHR?DINGER EQUATION WITH REFLECTIONLESS POTENTIAL WELL
ZHOU GUANG-HUI
1993, 42 (2): 173-179. doi: 10.7498/aps.42.173
Abstract +
Using a transformation of hyperbolic function, the Schr?dinger equation with reflection-less potential well is transformed into an associated-Legendre equation. Then both bound and scattering state eigenfunctions are expressed in terms of associated-Legendre polynomials and functions respectively. The exact solutions obtained in this paper are more general and systematic than some asymptotic solutions or solutions of reflectionless potential with special parameters in literatures. The normalization of the scattering state is discussed in detail.
DOUBLE WAVE DESCRIPTION OF THE MOTION OF A CHARGED PARTICLE IN A UNIFORM MAGNETIC FIELD
HUANG XIANG-YOU, LIU QUAN-HUI, TIAN XU, QIU ZHONG-PING
1993, 42 (2): 180-187. doi: 10.7498/aps.42.180
Abstract +
Double wave quantum theory is applied to describe the motion of charged particle in a uniform magnetic field. This description of the motion of the particle is complete. One can tell the value of an arbitrary physical quantity at any time. The probability and the formula to calculate mean values in ordinary quantum mechanics comes from the average of double wave description over a certain ensemble. The rule of gauge transformation in quantum mechanics can be seen from the average over an ensemble.
A NONSTATIC PLANE-SYMMETRIC SOLUTION OF EINSTEIN EQUATIONS WITH A SPECIAL SCALAR FIELD
LI JIAN-ZENG
1993, 42 (2): 188-192. doi: 10.7498/aps.42.188
Abstract +
A nonstatic solution of plane-symmetric metric generated by a special scalar field V = V(t-z) has been obtained. The global properties, such as its symmetries, singularities, are also investigated.
A COMMENT ON "GENERAL CONSERVATION LAWS IN EINSTEIN-CARTAN THEORY"
LI CHENG-YAO
1993, 42 (2): 193-197. doi: 10.7498/aps.42.193
Abstract +
In this paper, it is proved that if both general displacement of coordinates and the Lie derivative of vierbeins are treated as symmetric transformation, then it is impossible to obtain the called general covariant energy-momentum conservation laws in Einstein-Cartan theory byNoether theorem.
RENORMALISED STRESS-ENERGY TENSOR OF CONFORMAL SCALAR FIELD IN BOULWARE STATE IN REISSNER-NORDSTR?M SPACE-TIME
HUANG CHAO-GUANG
1993, 42 (2): 198-204. doi: 10.7498/aps.42.198
Abstract +
The renormalised stress-energy tensor of a conformal invariant scalar field in the Boul-ware stale in Reissner-Nordstr?m sapace-time is calculated by using the Page-Zannias method and with the help of a personal computer and REDUCE language. The tensor vanishes inthe asymptotically flat region and is not regular at the event horizon.
RELATION AMONG THE LATTICE VIBRATIONS, CARRIERS AND HIGH-Tc SUPERCONDUCTIVITY
ZHANG GUANG-YING, ZENG WEN-SHENG
1993, 42 (2): 205-213. doi: 10.7498/aps.42.205
Abstract +
The relation among the lattice vibrations, carriers and high-Tc superconductivity is discussed in detail. We propose that there are strong local coupling between carriers and rhe lattice vibrations rather than the screen effect between them. Basing on the experimental results and the theoretical analysis, we found that the relation between superconductivity and the strength of the local coupling and its overall effect.
THE PHYSICS OF ELEMENTARY PARTICLES AND FIELDS
BREAKING OF SUPERSYMMETRY AND WITTEN INDEX IN TWO-DIMENSIONAL SUPERSYMMETRIC MODELS
CHEN XIONG-XIONG, YU YANG-ZHENG
1993, 42 (2): 214-222. doi: 10.7498/aps.42.214
Abstract +
We construct a wider class of O(N) supersymmetric (SUSY) models with so-perpotential W = (l/n)gφn in two-dimensions. The witten index △ of the models is evaluated in detail. It is shown that SUSY breaking does not occur when n is even, and can occur when n is odd. By using large-N expansion, a mechanism for spontaneous SUSY breaking is investigated. Finally, we present the particle spectra.
ATOMIC AND MOLECULAR PHYSICS
RADIATIVE AND AUGER RATES OF HIGH DOUBLY EXCITED INTERSHELL STATES
GOU BING-CONG
1993, 42 (2): 223-230. doi: 10.7498/aps.42.223
Abstract +
The radiative and Auger rates are calculated for doubly excited intersh-ell states of Ar16+. We adopt the conventional infiguration interraction CI app-roach, bul each state is labelled using the n(K,T)NA2s+1Lπ designation. lt is shown that, to intrashell states which all have A = +1, these states decay prima-rily by auger process and radiative decay contributed significantly only for the hi-ghest states within a given manifoid, but to intershell states the Auger widths are much smaller tor A =-1 and A = 0 states. For these states the flourescence yield may become non-negligible. The approximate selection rule v=- 0,±1 for radiative decay holds for these states as well.
DEPENDENCE OF FIELD-IONIZATION THRESHOLD ON |ml| FOR RYDBERG STATES OF Sr ATOM
LI JING, XU YUN-FEI, WANG YUN-XIAN, ZHANG SEN
1993, 42 (2): 231-236. doi: 10.7498/aps.42.231
Abstract +
We have obtained Rydberg atom of different |ml| value by two-step excitation using polarized lasers. The field-ionization thresholds for 5snd (n= 22-27), | ml| =0,1,2 Rydberg states of Sr atom is measured by using a pulse electric field (up to 2.4kV/cm). Second-order approximate formula of field-ionization threshold that depend on the |ml| value is obtained and compared with the measured data.
IMPROVED KELDYSH-FAISAL-REISS THEORY
CHEN BAO-ZHEN
1993, 42 (2): 237-243. doi: 10.7498/aps.42.237
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In the framework of Keldysh-Faisal-Reiss (KFR) theory, with taking the coupling bet-ween the atomic potential and the applied light fields into account, the original KFR theory is improved and a new expression of photoionization probability of atoms is obtained.From this new expression, photoelectron spectra of H-atom ATI by strong linear-polarized laser in the short-pulse regime are got. This calulated photoelectron spectra are rather similar to the experimental ones. A new explanation of the experimental spectra is given.
AB-IN1T1O MOLECULAR DYNAMICS STUDIES ON GALLIUM CLUSTERS
GONG XIN-GAO, ZHENG QING-QI
1993, 42 (2): 244-251. doi: 10.7498/aps.42.244
Abstract +
The ab-initio molecular dynamics method and simulated annealing technique have been used to study the structural properties of small gallium clusters. We have found a transition from planar to nonplanar structure at n=5. Ga, molecule and zig-zag chain are building blocks of gallium clusters.
CLASSICAL AREA OF PHENOMENOLOGY
EXTERNAL-FIELD-INDUCED COHERENCE AND LASING WITHOUT INVERSION: THE V-TYPE SYSTEM
LUO ZHEN-FEI, XU ZHI-ZHAN
1993, 42 (2): 252-255. doi: 10.7498/aps.42.252
Abstract +
The conditions for realizing lasing without inversion are investigated via density matrix method in bare and dressed states in the V-type closed lifetime-broadened system where atomic coherence is induced by an external electromagnetic field. It is shown that a proper choice of pumping rate may lead to the realization of lasing without inversion.
LASER GINZBURG-LANDAU EQUATION AND ITS PHASE DIFFUSION EQUATION
WANG KAI-GE
1993, 42 (2): 256-263. doi: 10.7498/aps.42.256
Abstract +
The dynamical behavior of laser Ginzburg-Landau equation, which describes the sponta-neously spacial temporal symmetry breaking, has been investigated, In the case of inhomoge-neous stationary solution, it shows the cooperative frequency locking; and in the case of spa-tial-temporal oscillatory solution, all the transverse modes have a common optical carrier fre-quency. However, a chaotic solution can be generated at lower pumping, due to the diffraction of electro-magnetic field and nonlinearity. The numerical results show that, in the situation of small detuning, the reduced phase diffusion equation of this model can more precisely du-plicate its global dynamical behavior. It illustrates that the phase pattern of field guides the dy-namics in spontaneous formation of the transverse pattern of field.
DIRECT OBSERVATION AND RECORD OF THE PHASE CONJUGATION OF PICOSECOND OPTICAL PULSES
SHE WEI-LONG, LI QING-XING, YU ZHEN-XIN, GAO ZHAO-LAN, MO DANG, ZHU DE-RUI
1993, 42 (2): 264-272. doi: 10.7498/aps.42.264
Abstract +
The phase conjugation of picosecond optical pulses is observed and recorded directly by using a streak camera. The signals are achieved by holographic phase conjugate technique. A theory is presented which fits the experimental data well.
PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES
SPATIAL DISTRIBUTIONS OF X-RAY LASING LINEWIDTH AND ELECTRON DENSITY IN A Li-LIKE SILICON PLASMA
LU PEI-XIANG, ZHANG ZHENG-QUAN, XU ZHI-ZHAN, FAN PIN-ZHONG, SHEN BAI-FEI, CHEN SHI-SHENG
1993, 42 (2): 273-276. doi: 10.7498/aps.42.273
Abstract +
Through analysizing the spatial distribution characteristics of the linewidth of Li-like si-licon ions X-ray lasers, we show that Stark broadening is the main line broadening me-chanism for Li-like Si11+ ions recombine X-ray laser. Spatial distribution of the electron den-sity of gain medium obtained by Stark brcadening shows that the electron density in the gain region is about 1019/cm3, and the lasing linewidth and electron density are 0.21? and 2.9 × l019/cm3 at the gain maximum respectively.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
A DYNAMICAL CONVERGENCE CRITERION FOR THE REAL-SPACE MULTI-SLICE IMAGE SIMULATION METHOD
ZHU SHI-XUE, WANG YUAN-MING, WANG SHAO-QING, YAN DE-QIN, JIN ZHI-XIONG
1993, 42 (2): 277-282. doi: 10.7498/aps.42.277
Abstract +
This paper gives a new dynamical convergence criterion (RSMSD) in the real space multi-slice (RSMS) method, which imposes a practical restriction in choosing dynamically the expan-sion order for the propagator between each pair of slices by using a structure-dependent trun-cation condition, so as to avoid the intrinsic computational divergence problem of the original RSMS method. The validity of the RSMSD method for dynamical diffraction calculation in HREM has been rigorously examined. It has been found that, when the dynamical criterion is satisfied, the RSMSD method gives results in good agreement with those obtained by using fast Fourier transform multi-slice (FFTMS) method but avoiding the computing divergence which can arise in the RSMS method.
STRUCTURES AND MICRODYNAMIC BEHAVIOR OF LIQUID TRANSITION METAL Pd AND Pt
CHEN KUI-YING, LI QING-CHUN, CHEN XI-CHEN
1993, 42 (2): 283-289. doi: 10.7498/aps.42.283
Abstract +
On the basis of the embedded atom model reflecting many body interactions among atoms and the effective pair potential, structures and microdynamic behavior of liquid transition me-tal Pd and Pt have been investigated by means of molecular dynamics simulation with compu-ter. Pair distribution function, mean square displacement, self-diffusion coefficients and nor-malization velocity self-correlation function have been calculated, and the influence of many body interactions on these physical quantities have been discussed. Results show that the inf-luence of many body interactions on the pair distribution function is small, but this influence on mean square displacement, self-diffusive coeffcients and normalization wlocity self-correla-tion function is cons derable.
DETERMINATION OF ORDERED STRUCTURES IN FACE-CENTRED CUBE INTERSTITIAL SOLUTIONS
NI JUN, WANG SHI-FAN
1993, 42 (2): 290-296. doi: 10.7498/aps.42.290
Abstract +
The probability wave theory of atomic configuration is employed to study the most stable superlattices formed in fcc interstitial solutions. Eight basic ordered structures are deduced for octahedral interstices and seven basic ordered structures are deduced for tetragonal interstices.
TRANSFORMATION TEMPERATURE OF GRAIN BOUNDARY RELAXATION IN ALUMINIUM BICRYSTALS
DUAN YU-HUA, GE TING-SUI, ZHANG TIAN-YI
1993, 42 (2): 297-303. doi: 10.7498/aps.42.297
Abstract +
Anelastic creep curves of [110] symme rical tilt boundaries with mis-orientation angles 60°and 153.4°in aluminium bicrystals has been measured in torsion. It was found that the relaxation strength associated with the boundary becomes zero below a temperature T0 which has a value of about one half of the melting temperature Tm of bulk aluminium. This shows that a perceptible change of the internal structure of the grain boundary has taken place around this temperature.
PERCOLATION MECHANISM OF SUPERLATTICE PHASE TRANSITION OF INTERMETALLIC COMPOUNDS
ZHENG MAO-SHENG, LIU YUN-PENG
1993, 42 (2): 304-308. doi: 10.7498/aps.42.304
Abstract +
In the present paper, superlattice phase transition and toughening of intermetallic compo-unds are studied. By writting the Hamiltonian of superlattice phase transition as the Ising's one, the expression of short-range-order parameter in superlattice phase transition P′ =1-exp (-2J/kT) is derived based on the correspondence of Ising model and bond percolation. The phase transition points of superlattice phase transition for systems with L10 and L12 structures are ther obtained by Monte-Carlo simulation, which is P′bc = 0.3436 (for Llo structure), P′bc= 0.4924 (for L12 structure). Furthermore, the relationship between P′bc and the corresponding values Pbc of general percolation process with the same nominal structure P′bc x=Pbc is for-mulated. Finally, the influence of composition variable x to the phase transition point, the or-dering and the brittleness of intermetallic compounds is expounded theoretically. It provides the theoretical basis for the toughening of intermetallic alloys, and also enriches percolation theory.
A STUDY ON STRUCTURAL STABILITY OF BUFFER LAYER BETWEEN SILICON SUBSTRATE AND DIAMOND FILM
ZHANG XIAO-PING, GAO ZHI-QIANG, SUN BI-WU, XIE KAN, LIN ZHANG-DA
1993, 42 (2): 309-313. doi: 10.7498/aps.42.309
Abstract +
High-quality diamond films are grown on Si substrate by hot filament chemcial vapor de-position (HFCVD). With increase of growth time, pure carbon species and mixtures of them are also identified by X-ray photoelectroscopy (XPS) and auger electron spectroscopy (AES). To describe the buffer layers, a gradient model is proposed as Silicon/Si1-xCx/SiC/SiyC1-y/ Diamond. Within the range of 0.10
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
STUDY ON STRUCTURAL AND VIBRATIONAL PROPERTIES OF AMORPHOUS SILICON FILMS USING A SIMULATING ANNEALING MODEL
YU GONG, HAO MAO-SHENG, ZHANG FANG-QING, CHEN GUANG-HUA
1993, 42 (2): 314-319. doi: 10.7498/aps.42.314
Abstract +
We have performed simulating annealing in computer by using Monte Carlo technique to produce a random-network model of amorphous silicon. The structural characteristics of this model is in good agretment with that of real sample. Its vibrationol densities of states have been calculated with molecular-dynamics method. The relationships between its locaiized vibrational modes and the structural defects have also been discussed.
INVESTIGATION OF ELECTRONIC STRUCTURE IN THE HYDROGEN-INDUCED STRUCTURAL TRANSITION FROM DIAMOND C(111)-(2×1) TO (1×1)
PAN BI-CAI, XIA SHANG-DA
1993, 42 (2): 320-325. doi: 10.7498/aps.42.320
Abstract +
The electronic structure of diamond C(111) surface during transition from (2×1) recons-truction to (1×1) structure induced by adsorbed hydrogens is studied using ab initio DV-Xα mathod in this paper. The result shows that the role of adsorbed hydrogen in the structural transition is firstly distorting the Pandey π-bond in the (2×1) reconstruction, then breaking the (SP2-hybrid + Pandey π-bond) structure and forming the sp3-hybrid bonds.
DETERMINATION OF OXYGEN CONTENT IN HIGH Tc SUPERCONDUCTORS BY DEUTERON PARTICLE ACTIVATION ANALYSIS
D.E. AlBURGER, K.W. JONES, Y.D. YAO, Y.H. KAO, TAO ZHEN-LAN
1993, 42 (2): 326-330. doi: 10.7498/aps.42.326
Abstract +
The experimental method for determining the oxygen content in high Tc superconduc tors is described in detail. This method is applied to determination of oxygen content in high Tc Y-Ba-Cu-O and Bi-Sr-Ca-Cu-O samples in which the stoichiometry is varied by reducing the copper and bismuth concentrations. The oxygen concentration is found to vary linearly with Cu (x= 0-0,2) and Bi (x= 0-0.4) deficiencies in YBa2Cu3(1-x)Oy and Bi2(1-x)Sr2CaCu2Oy respectively. X-ray powder diffraction measurements show that the compound of YBa2Cu3(1-x)Oy, is orthorhombic in the variation range of x=0-0.2
HIDDEN LOCAL GAUGE INVARIANCE IN FATEEV-ZAMOLO-DCHIKOV QUANTUM SPIN CHAIN
GUAN XI-WEN, XIONG ZHUANG, ZHOU HUAN-QIANG
1993, 42 (2): 331-339. doi: 10.7498/aps.42.331
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Hidden local gauge invariance in Fateev-Zamolodchikov quantum spin chain is studied in detail in the framework of the quantum inverse scattering method (QISM). It is found that, similar to the case of spin 1/2, this model admits an Abelian U(1) gauge transformation and that the energy spectrum is gauge invariant whereas the eigenvectors are explicitly gauge dependent.
STUDIES ON ELECTRIC CONDUCTIVITY AND ELECTRON SPIN RESONANCE FOR IODINE DOPED POLYACETYLENE
GUI YUN-LONG, LIN SEN-HAO, ZHANG JIA-HUA
1993, 42 (2): 340-344. doi: 10.7498/aps.42.340
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The four-probe technique is used to measire the electric conductivity of polyacetylene doped with iodine. For dopant concentration ranging from 1.0 to 8.3 mol% in cis-(CH)x, the obtained conductivity values for different temperatures are consistent with the variable-range hopping model. The mechanisms of the temperature dependence of the ESR spin magnetic susceptibility and line width for low iodine concentrations are studied.