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Vol. 43, No. 11 (1994)

1994-06-05
ATOMIC AND MOLECULAR PHYSICS
INTERELECTRONIC CORRELATION AND QUALITATIVE FEATURES OF THE FOUR INTRASHELL P STATES OF BORON ATOM
BAO CHENG-GUANG
1994, 43 (11): 1745-1753. doi: 10.7498/aps.43.1745
Abstract +
The qualitative features of the four intrashell P states of the boron atom, i.e., the 2P01 (ground state), 2P02,2Pe1 and 4Pe1 states, are investigated. The interelectronic correlation is found to be strongly spindependent. The preferrence of orientation (redative to the total angular momentum) is found to be explicit. The geometric structures of relevant states and the modes of internal motion have been investigated. The decisive effect of quantum mechanical symmetry has been emphasized.
EXPERIMENTAL STUDY OF RELATIONS BETWEEN |ml| AND FIELD STARK IONIZATION THRESHOLD IN RYDBERG Cs ATOMS
DING GUANG-LIANG, LIU BING-MO, WANG JIA-MIN, GONG SHUN-SHENG
1994, 43 (11): 1754-1758. doi: 10.7498/aps.43.1754
Abstract +
The experimental study of the relations between |ml| and field ionization thresholds of Stark components in Rydberg states of atomic cesium is reported. The three expressions of ionization thresholds of |ml|=0,1,2 in atomic cesium are obtained completely from the same experiment.
INVERSE SCATTERING THEORY FOR ELECTRON COLLISION WITH ATOMS AND MOLECULES
CHEN XUE-JUN, WANG YAN, LI BO, DENG XIN-YUAN
1994, 43 (11): 1759-1763. doi: 10.7498/aps.43.1759
Abstract +
A brief of the parameterized inverse scattering methods including WKB and quantum-approaches are described at first and then,these methods are tested in detail by an example of model potential.
A STUDY ON THE BEHAVIOR OF THE ALIGNMENT FOR L3 VACANCY STATE IN Au BY IMPACT IONISATION
XIA ZONG-HUANG, MA HONG-JI, FU SHENG-CHUN
1994, 43 (11): 1764-1769. doi: 10.7498/aps.43.1764
Abstract +
In low projectile energy region, the alignment of L3 vacancy state in Au and the projectile energy dependence of alignment were measured for several kinds of ions and Au collision systems by a simple method. Using the plane-wave Born approximation (PWBA) and taking into account the coulomb deflection effect, the alignment was calculated. It is shown that the present calculated results are closer to the experimental data. The alignment behavior of L3 vacancy state in Au is furtherly discussed.
CLASSICAL AREA OF PHENOMENOLOGY
STUDIES OF THE REAL-TIME OPTICAL CORRELATION STORAGE IN LiNbO3:Fe Photorefractive Crystals
LIU SI-MIN, SHU HUA-DE, SUN QIAN, ZHANG GUANG-YIN, XU JING-JUN, LIU JUN-MIN, LU YI
1994, 43 (11): 1770-1775. doi: 10.7498/aps.43.1770
Abstract +
The real-time optical correlation-storage in photorefractive crystals has firstly been realized. It possesses the advantages of both storage and correlator, as well as the real-time character of photorefractive devices. It can performa real-time and fast selection of imformation correlated to the input ones from a great amount of stored imformation. The correlation degree of every information with the input ones and its coding number are immediately obtained from the intensity and position of the correlation points. This principle is based on the selectivity of photorefractive matched filter. Hence this device has wide prospect of application.
EVOLUTION OF THE FIELD ENTROPY IN JAYNES-CUMMINGS MODEL WITHOUT ROTATING-WAVE APPROXIMATION
FANG MAO-FA
1994, 43 (11): 1776-1786. doi: 10.7498/aps.43.1776
Abstract +
The evolution law of the field entropy in the J-C model without rotating-wav approximation are invesitigated. Comparing with the results obtained with the rotating-wave approximation, the influence of the virtual photon processes on the evolution of the field entropy are discussed.
STATISTICAL PROPERTIES OF SU(1,1) COHERENT STATES OF LIGHT AND ITS INFLUENCE ON DYNAMICAL BEHAVIORS OF THE ATOM
LU HONG, PENG JIN-SHENG
1994, 43 (11): 1787-1794. doi: 10.7498/aps.43.1787
Abstract +
In this paper, we study the properties of two kinds of SU(1,1) coherent states of light with Bargman index k=1/4 and k=3/4 and show that they posses different quantum statistical properties. The atomic dynamical behavior in a two-photon Jaynes-Cummings model with initial SU(1,1)coherent state field are discussed. We show that the time evolution of atomic inversion displays peculiar periodic oscillation and pulse which are very different from coherent states of light.
STUDY OF HARD-DESTRUCTIVE MECHANISM OF THE CHARGE-COUPLED DEVICES BY A LASER
NI XIAO-WU, LU JIAN, HE AN-ZHI
1994, 43 (11): 1795-1802. doi: 10.7498/aps.43.1795
Abstract +
Theoretical and experimental study has been made for the process of hard-des-truction produced by a laser acting upon the surface of charge-coupled devices (CCD) having the MOS structere. It is suggested that the thermal action of laser and the mechanical action of laser plasma shock wave are the main causes for destruction of the structure of the CCD. Optical breakdown threshold, visible damage threshold, thermal melting threshold of semiconductor materials of the CCD device by YAG laser and laser energy threshold caused the whole device to faiture are obtained.
SMALL-AMPLITUDE SOLITONS SUPPORTED BY THE SELF-STEEPENING EFFECT IN OPTICAL FIBERS
CHEN LU-JUN, LIANG CHANG-HONG, WU HONG-SHI
1994, 43 (11): 1803-1808. doi: 10.7498/aps.43.1803
Abstract +
Based on the small-amplitude approximation on a CW pedestal, the role of self-steepening effect in nonlinear dynamics and transmmision of soliton in normal and anomalous dispersion regions is investigated. The results show that, by taking into account the loss and gain, as well as the self-induced Raman effect, there exist both bright and dark small-amplitude solitons in both normal and anomalous dispersion regions. Especially, there exist the types of solitons opposite to the ordinary types of bright or dark solitons in both regions.
CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES
STUDY OF EFFECTS OF LOW-ENERGY BOMBARDMENTS OF Si(001)-2×1 BY MOLECULAR DYNAMICS SIMULATION
JIA ZHENG-MING, YANG GEN-QING, CHENG ZHAO-NIAN, LIU XIANG-HUAI, ZOU SHI-CHANG
1994, 43 (11): 1809-1815. doi: 10.7498/aps.43.1809
Abstract +
Molecular dynamics simulations were performed for 1-100eV particle bombardments of Si(001)-2×1 surface. The two dimensional pair correlation functions were obtained to investigate the arrangement of surface atoms after such bombardments. The results show that 10eV and 100eV bombardments had the some effects on the behaviour of surface atoms. On one hand, 10eV and 100eV bombardments improved the mobility of surface atoms and produced more dimers. On the other hand, they increased the disordering of surface atom's arrangement and made the surface tend to be amorphous.
LOCALIZATION OF THE COMPONENT ATOM DEPTH-PROFILES IN Al-Sn ALLOY SURFACE LAYER
WANG ZHEN-XIA, PAN JI-SHENG, ZHANG JI-PING, ZHU FU-YING
1994, 43 (11): 1816-1820. doi: 10.7498/aps.43.1816
Abstract +
The Sn atom depth-profiles in the micro-phase region of the Al70Sn30 alloy surface for before and after the 27keV Ar+ ions bombardment have been studied using micro-beam Rutherford backscattering spectroscopy (M-RBS) analysis methods. The experimental results shown that the depth-profiles of the Sn atom between Al-rich phase region and Sn-rich phase region, and these phase regions locate on the unsputtered and sputtered surface are different.
A STUDY ON THERMAL PROPERTIES FOR ZrO2 COATINGS BY ARC PHOTOTHERMAL TECHNIQUE AND FINITE-DIFFERENCE THERMAL FLOW MODEL
DU YING-LEI, WU BAI-MEI
1994, 43 (11): 1821-1827. doi: 10.7498/aps.43.1821
Abstract +
The thermal conductivity and thermal diffusivity of ZrO2 coatings were studied using arc-photothermal evaluation technique in which the sample was heated at front surface and detected at back surface, and finite-difference thermal flow model was applied. The values of thermal conductivity and thermal diffusivity of ZrO2 are k=0.0069J/cm·K·s and α=0.0028cm2/s, respectively. It is shown that, first, the finite-difference thermal flow model is an available and useful method for the multilayer coating system, and, second, the arc photothermal evaluation technique has low cost of equipment, and more simple and convenient measurement.
CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES
ELECTRON CORRELATION EFFECT IN THE HUBBARD-HIRSCH MODEL
WEI GUO-ZHU
1994, 43 (11): 1828-1832. doi: 10.7498/aps.43.1828
Abstract +
Based on the single-site electron correlation, the local approach has been used to investigate the ferromagnetic phase in the Hubbard-Hirsch model. Using the R =0,α approximation in second-order calculation, the electron Correlation effect on the phase diagram has been studied Carefully. Comparing with those of the R=0 approximation, the electron correlation effect becomes weaker due to taking into aceount the nondiagonal elements of density matrix.
ELECTRON CORRELATION EFFECT ON C60 EXCITON POLARON
FU RONG-TANG, SUN XIN, HUANG QING-PENG, FU ROU-LI
1994, 43 (11): 1833-1839. doi: 10.7498/aps.43.1833
Abstract +
Exciton polaron states in C60 molecular are theoretically studied in the tight-binding approach supplemented by the extended Hubbard interaction. The binding energies of the lowest singlet and triplet excitons depend sensitively upon the electron correlation. Then the exciton polaron is formed due to the electron-lattice coupling. Relevent experiments in photo-luminescence spectrum of Cso can be explained qualitatively by the present model with moderate interaction strength U~5.0eV,V~2.0eV.
MECHANISM OF CONDUCTION IN BaSn1-xSbxO3-δ AND Ba1-yLaySnO3-δ
TETSURO NAKAMURA, HUANG TONG-KAI
1994, 43 (11): 1840-1846. doi: 10.7498/aps.43.1840
Abstract +
The temperature dependence of resistivity and magnetic susceptibility was measured for both BaSn1-xSbxO3-δ and Ba1-yLaySnO3-δ systems below room temperature. The results show that the mechanism of conduction is the variable range hopping for both systems at lower temperature. Whereas the two types of mechanism of conduction at higher temperature, are considered the nearest-neighbor hopping (Ba1-yLaySnO3-δ)and as the excitation of electrons to the conduction band (BaSn1-xSbxO3-δ)
PROPERTIES OF INTERFACE OF a-Si:H/a-SiCx: H SUPERLATTICE
CHEN GUANG-HUA, GUO YONG-PING, YAO JIANG-HONG, SONG ZHI-ZHONG, ZHANG FANG-QING
1994, 43 (11): 1847-1853. doi: 10.7498/aps.43.1847
Abstract +
The a-Si: H/a-SiCx: H superlattices were fabricated by r. f. plasma CVD. The blue shift of optical bandgap and construction of the superlattices were present. The interface abruptness was determined by low-angle X-ray diffraction. The constant photocurrent method and IR measurement showed that there existed excess hydrogen and high concentration of Si-C bonds at a-Si:H/a-SiCx:H interfaces. The thermal stability of interfacial hydrogen was poor. The interfacial defect density was about 1.2×1011cm-2.
ION SIZE EFFECT OF Tc-PLATEAU IN R1-xPrxBa2Cu3O7-δ
CAO XIAO-WEN, Y. J. TANG, J. C. HO
1994, 43 (11): 1854-1859. doi: 10.7498/aps.43.1854
Abstract +
Dependence of superconducting Tc upon Pr-substitution concentration x was studied systematically in R1-xPrxBa2Cu3O7-δ system with R=Nd, Dy, Tm, Yb and Lu. It was found that there is a Tc-plateau in the range of low x as R3+ radius ri≤ri(Dy). The Pr-concentration width corresponded by Tc-plateau exhibits a R3+ ion size effect. We suggest that the ion size effect of Tc-plateau might result from the change of local state of Pr 4f electron. A critical R3+ radius, ric, is suggested and superconductivity disappears as ri>ric.
THE RELATIVE FERMI LEVEL POSITION AND THE ELECTRON-PHONON COUPLING OF YBa2Cu3O7-δ STUDIED BY FEMTOSECOND TRANSIENT REFLECTIVITY
XIONG GUANG-CHENG, ZOU YING-HUA, XIA ZONG-JU, YUAN PING, LIAN GUI-JUN, LI JIE
1994, 43 (11): 1860-1865. doi: 10.7498/aps.43.1860
Abstract +
The femtosecond pulsed laser and pump-probe method have been used to measure the transient change of reflectivity of YBa2Cu3O7-δ(δ=0.0, 0.1, 0.4 and 0.8) thin films. From the experimental curves the transient changes are found to be very different for samples with different oxygen content. The sign of the changes can be reversed as decreasing the oxygen content. It may be attributed to the changes of energy band structure near the Fermi level. After fitting the experimental data, we reveal that the electron-phonon coupling in the sample of δ=0.4 is much weaker than high Tc(δ=0.0) sample.
STUDY ON THE FERROMAGNETIC STATE IN QUASI-ONE-DIMENSIONAL ORGANIC FERROMAGNETIC
FANG ZHONG, LIU ZU-LI, YAO KAI-LUN, LI ZAI-GUANG
1994, 43 (11): 1866-1870. doi: 10.7498/aps.43.1866
Abstract +
The ferromagnetic state in quasi-one-dimensional organic ferromagnet poly-SIPO has been studied. We consider the electron hoping, electron-electron correlation and Pierls instability in one-dimensional system. And self-consistent calculations are performed to investigate the structure of energy band and the distribution of spin density. The effects of the above aspects on the ferromagnetic state are studied. The results show that the ground state is a stable ferromagnetic state in this system.
ELECTRON SPIN RESONANCE STUDY ON RADIOLYTIC DEFECT IN OPTICAL FIBER
LIU FANG-XIN, ZHANG CHEN-HUA, XUAN ZHI-HUA, LI ZONG-MING, JIN SI-ZHA0
1994, 43 (11): 1871-1875. doi: 10.7498/aps.43.1871
Abstract +
The γ-ray radiolytic defect in optical fiber has been studied by the electron spin resonance method. It is found that a series of paramagnetic defects have been formed by the γ-ray irradiation; the densities of the defect centers increase with the irradiation doses, and the types of defects are mainly the E′ center, the non-bridging oxygen hole center and the perody radical (OHC). The defects production mechanism is also discussed.
ANALYSIS ON Ag/Ag2O ULTRAFINE PARTICLE PREPARED BY SPUTTERING
LI JIAN, LIU CUN-YE, LIANG YI-PING, REN HONG-XIANG, DENG ZHAO-JING, LIU CHANG-XIN
1994, 43 (11): 1876-1882. doi: 10.7498/aps.43.1876
Abstract +
The crystal phase, surface composition, particle shape and thermodynamic chaxacter of Ag ultrafine particle (UFP), which were prepared by sputtering in Ar gas, have been analysed by means of X-ray diffraction, X-ray photo-electron spectrum, transmission electron microscope (TEM) and differential scanning calorimeter. The results show that the particles with size larger than 4.6nm are composed of Ag-nuclens and Ag2O-surface-layer, the particles with size less than 4.6nm consisted of Ag2O only, the shape of particles with size less than 10nm are spherical and that with size larger than l0nm are non-definte when the particle were as-prepared. It is shown by DSC that there are different thermal effect between UFP and solid Ag. Also, it is shown by TEM that a few particles which had two phase of Ag and Ag2O and deposited on the carbon film have been reduced to metal Ag UFP after 40 days.
DYNAMIC STORAGE TIME MEASUREMENTS OF N-TYPE Hg1-xCdxTe METAL-INSULATOR-SEMICONDUCTOR DEVICES
HUANG HE, TANG DING-YUAN, TONG FEI-MING, ZHENG GUO-ZHEN
1994, 43 (11): 1883-1888. doi: 10.7498/aps.43.1883
Abstract +
Dynamic storage time has been measured for x=0.31 n-type Hg1-xCdxTe metal-insulator semiconductor (MIS) devices over temperature range of 68 to 250K. The theoretical calculations have been made in analysing the mechanisms of dark currents. The results point out that the indirect tunnel current, which involves a thermal transition of an electron from the valence band to a band-gap state followed by tunneling into the conduction band, is the main dark current source, especially in low-temperature (about 77K) high-field regime and will dominate the electrical properties of the MIS devices.
A STUDY ON DISSOCIATION KINETICS OF SiH4+CH4 PLASMA INDUCED BY PULSED INFRARED LASER
YU WEI, LI XIAO-WEI, HAN LI, ZHANG LIAN-SHUI, FU GUANG-SHENG
1994, 43 (11): 1889-1898. doi: 10.7498/aps.43.1889
Abstract +
The time-resolve optical emission spectroscopy is used to study silane and methane laser plasma. The results show that the different fragments' characteristic lines has the same appearance time but different temporal behaviours when the reactant breaks down. Based on the experimental results of dissociation processes it is suggested that the producing of Si and C atoms is the main dissociation channels of the reaction.
GEOPHYSICS, ASTRONOMY, AND ASTROPHYSICS
STATIC DYON BLACK HOLE FOR COUPLED SU(5) EYMH SYSTEM
JING JI-LIANG, YU HONG-WEI, WANG YONG-JIU, TANG ZHI-MING
1994, 43 (11): 1899-1906. doi: 10.7498/aps.43.1899
Abstract +
Coupled SU(5) Einstein-Yang-Mills-Higgs system is studied. A family of static spherical symmetric dyon soiutions and the space-time metrics of the Reissner-Nord-strom type are obtained. The solutions represent static dyon black holes with ma gnetic charge ±3/2e.
WORMHOLE SOLUTION IN VACUUM REAL BRANS-DICKE THEORY
LIU LIAO, XIAO XING-GUO
1994, 43 (11): 1907-1912. doi: 10.7498/aps.43.1907
Abstract +
In this paper, we give an Euclidean wormhole solution in the vacuum Brans-Dicke theory, which is different from that obtained by Accetta et al. We show that this wormhole unlike all the others, it's throat dimension increases linearly with the increasing of the Euclidean cosmic time.