中国物理B

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GENERAL JAHN-TELLER POTENTIALS WITH MANY ELECTRONS

陈峰, 李文铸

1996 (5): 321-329. doi: 10.1088/1004-423X/5/5/001

摘要 ( 1075 )

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The present paper investigates the Jahn-Teller theory for the case that the degenerate molecular energy level is occupied by many electrons. The Oepik-Pryce treatment and the isostationary function method are used to determine the structure of the Jahn-Teller potential, whose symmetric properties are discussed. Examples are given for $\varGamma$×($\varLambda$₁ + $\varLambda$₂) Jahn-Teller problems.

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COMPETITION EFFECT IN ATOMIC-MOLECULAR SYSTEM

贾锁堂, 秦莉娟, 钱祖良, 王祖赓, 王钢, 周国生

1996 (5): 330-336. doi: 10.1088/1004-423X/5/5/002

摘要 ( 933 )

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The competition effects among the processes that occur in the two-photon 3S→4D excitation of Na atom in Na-Na₂ vapour mixture are observed: such as atomic ionization, optical-pumped stimulated radiation, four-wave frequency mixing and molecular stimulated diffuse-band radiation, etc. The dip at the two-photon resonance in the excitation spectrum for the diffuse-band radiation under high temperature condition is interpreted as the suppression of population in 4D state.

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STUDY OF THREE-PHOTON RESONANCE MULTIPHOTON IONIZATION SPECTROSCOPY OF 3p RYDBERG STATES OF m-DIMETHYLBENZENE WITHIN DYE Rh560

刘耀明, 林美荣, 赵青春, 张包铮, 陈文驹

1996 (5): 337-342. doi: 10.1088/1004-423X/5/5/003

摘要 ( 1143 )

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In this paper, we studied experimentally the three-photon resonance four-photon ionization spectroscopy of m-dimethylbenzene within dye Rh560. We found several new 3p Rydberg vibronie states and measured their polarization characters. With the help of the measured polarization quantities, we gave the assignment results of these vibronic states: 9b₀¹, A₁; 13₀¹, A₁; 19a₀¹, A₁; 8a₀¹, A₁.

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APPROXIMATION THEORY OF OSCILLATING FACTOR SUPPRESSING AMPLITUDE IN QUANTUM PROCESS AND ITS APPLICATIONS

孙昌璞, 刘夏姬

1996 (5): 343-353. doi: 10.1088/1004-423X/5/5/004

摘要 ( 933 )

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The oscillating factor suppressing amplitude approximation is proposed in this paper as a basic method to study the evolution of a quantum system. By making use of this method, not only the quantum adiabatic approximation is described again, But also both the higher-order corrections for the rotation wave approximation and the influences of other levels on two-level approximation can be analytically investigated with the explicit discussion for the quantitative conditions under which the two approximations hold.

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DESIGN OF DIFFRACTIVE-PHASE AXICON ILLUMINATED BY A GAUSSIAN-PROFILE BEAM

张国庆, 董碧珍, 杨国桢, 顾本源

1996 (5): 354-364. doi: 10.1088/1004-423X/5/5/005

摘要 ( 1405 )

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The diffractive-phase axicon can convert the Gaussian-profile beam into axial uniform intensity distribution with long focal depth and high lateral resolution. Two types of phase-retardation functions for the nonuniform-illuminating axicon are derived in terms of the ray tracing and the geometrical law of energy conservation. Based on the general theory of the amplitude-phase retrieval in optical system and the iteration algorithm, the optimization design of the phase distribution of the diffractive-phase axicon can be achieved. The simulation celculations show that the new approach may successfully offer the design of the desired diffractive-phase axicon with long focal depth and high lateral resolution. A comparison of the performances of the holographic axicon with the phase-retardation functions from the geometrical optics prediction and the diffractive-phase axicon designed by the new approach is also presented.

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EFFECTS OF THE QUALITY OF SUBSTRATE ON THE STRUCTURE AND SUPERCONDUCTING PROPERTIES OF Yba₂Cu₃O_7-x THIN FILM

吕惠宾, 许世发, 田永君, 周岳亮, 崔大复, 陈正豪, 刘军政, 何萌, 李林, 杨国桢, 卢剑, 任向阳, 张其劭, 刘安生, 孙丽虹

1996 (5): 365-369. doi: 10.1088/1004-423X/5/5/006

摘要 ( 1051 )

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We have systematically investigated the structures, morphologies, microwave surface resistance, DC performances and the substrate qualities of three YBa₂Cu₃O_7-x(YBCO) thin films 30mm in diameter. The three samples deposited by the same process have been proved of different properties. It has been shown that the structure and superconducting properties of the thin film depend strongly on the quality of substrate.

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STUDY OF MOLECULAR BEAM EPITAXIAL GROWTH AND OPTICAL CHARACTERISTICS OF HgCdTe

郭世平, 张家明, 刘普霖, 沈学础, 袁诗鑫

1996 (5): 370-376. doi: 10.1088/1004-423X/5/5/007

摘要 ( 1010 )

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HgCdTe epilayers were grown by molecular beam epitaxy on GaAs(211)B substrates. Process of the HgCdTe epitaxial growth can be monitored by reflection high-energy electron diffraction. Results of the infrared transmission spectrum, Raman scattering spectrum and infrared photoluminescence spectrum in magnetic field have been studied.

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THIRD-ORDER NONLINEAR OPTICAL PROPERTIES OF SnO₂ NANOPARTICLES

余保龙, 张桂兰, 汤国庆, 吴晓春, 陈文驹, 杨斌洲, 赵平

1996 (5): 377-383. doi: 10.1088/1004-423X/5/5/008

摘要 ( 1163 )

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We have measured the third-order nonlinear susceptibilities χ⁽³⁾ of SnO₂ nanoparticles both naked and coated with a layer of stearic acid by using Z-scan technique with 1.06μm pulse from a Q-switched Nd:YAG laser. The results show that the χ⁽³⁾ of these nanoparticles is much larger than that of the bulk material. Moreover, we find that two-photon absorption is not present for the naked nanoparticles but it is preseut for the coated ones, and the χ⁽³⁾ of the latter is larger than that of the former. It is demonstrated that the surface situations of the nanoparticles have great influence on their nonlinear optical properties.

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PULSED LASER DEPOSITION AND CHARACTERIZATION OF FERHOELECTHIC Pb(Zr, Ti)O₃ THIN FILMS ON SILICON-ON-INSULATOR SUBSTRATES

郑立荣, 张顺开, 林成鲁

1996 (5): 384-390. doi: 10.1088/1004-423X/5/5/009

摘要 ( 762 )

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Ferroelectric Pb(Zr, Ti)O₃ thin films were prepared by pulsed exeimer laser deposition on silicon-on-insulator and Pt-coated silicon-on-insulator substrates, and rapid thermal annealing was per-formed to crystallize the films, Based on the analysis by X-ray diffraction, Rutherford backscattering spectroscopy and measurements of electrical properties, the films were revealed to be polycrystalline perovskite structure with mainly (100) and (110) orientations, and their crystallization was found to be dependent on annealing temperature and annealing time. The films show good ferroelectricity, with P_r=15μC/cm², E_c= 50kV/cm, high resistivity and high dielectric constant.

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