Table of contents

20 December 1995, Volume 4 Issue 12 Previous issue    Next issue

ATOMIC AND MOLECULAR PHYSICS

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PHOTOIONIZATION IN AN INTENSE LASER FIELD LIU JIE (刘杰), Chen Shi-gang (陈式刚), Bao De-hai (鲍德海) Acta Physica Sinica (Overseas Edition), 1995, 4 (12):  881-888.  DOI: 10.1088/1004-423X/4/12/001 Abstract ( 1458 )   PDF (200KB) ( 523 )   In this paper classical approaches are used to study the detailed processes of photoion-ization in an intense laser field. The analytic expression of the ionization rate is derived. Finally, the results obtained are compared with existing theories such as Landau's tunnel theory and Keldysh-Faisal-Reiss theory.

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FREQUENCY-MODULATION OPTICAL-OPTICAL TRIPLE-RESONANCE OPTICAL HETERODYNE SPECTROSCOPY JIANG HONG-JIE (江红杰), Ding Liang-en (丁良恩), Xia Hui-rong (夏慧荣), Wang Zu-geng (王祖庚) Acta Physica Sinica (Overseas Edition), 1995, 4 (12):  889-898.  DOI: 10.1088/1004-423X/4/12/002 Abstract ( 948 )   PDF (253KB) ( 347 )   We propose new frequency-modulation optical-optical triple-resonance (FM-OOTR) op-tical heterodyne spectroscopy, which can eliminate the Doppler-background in the recently developed optical-optical triple-resonance (OOTR) spectroscopy and provide improved reso-lution and sensitivity. Theoretical considerations and line shape calculations are presented. The potential applications of FM-OOTR technique to laser frequency stabilization with sig-nificant advantages can be expected.

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CHARGE STATES OF SPUTTERED ATOMS/IONS PAN LI-MIN (潘立民), Wang Yan-sen (王炎森), Huang Fa-yang (黄发泱), Tang Jia-yong (汤家镛), Yang Fu-jia (杨富家) Acta Physica Sinica (Overseas Edition), 1995, 4 (12):  899-905.  DOI: 10.1088/1004-423X/4/12/003 Abstract ( 1390 )   PDF (170KB) ( 418 )   The charge states of sputtered cesium and oxygen ions/atoms from metal surfaces have been discussed with the time-dependent Newns-Anderson model. The final charge state distribution has been calculated as a function of work function of the surfaces. The calculated results fit the experimental data well. Besides, the dependence of the final charge states of the sputtered oxygen particles on the surface temperature is also predicted.

PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES

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PRESSURE DEPENDENCE OF ELECTRON DENSITY DISTRIBUTION IN GLOW DISCHARGE GUO XIAO-MING (郭小明), Zhou Ting-dong (周庭东), Pai Siu-ting (白秀庭) Acta Physica Sinica (Overseas Edition), 1995, 4 (12):  906-911.  DOI: 10.1088/1004-423X/4/12/004 Abstract ( 1189 )   PDF (151KB) ( 652 )   Based on a glow discharge model of analytic form developed recently and by using the available data for the diffusion coefficients and mobilities of electrons and positive ions, the pressure effects on the spatial distribution of the electron density n have been systematically calculated and analyzed, The gas employed in the study was pure argon and the pressure range was from 0.1 to 1Torr. Theoretical results were found to be consistent with the experimental observations.

CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES

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NEUTRON-POWDER-DIFFRACTION STUDY OF ErFe11.35Nb0.65 AND ErFe11.35Nb0.65Ny SUN XIANG-DONG (孙向东), Yan Qi-wei (严启伟), Zhang Pan-lin (张泮霖), Hu Bo-ping (胡伯平), Wang Kai-ying (王开鹰), Wang Yi-zhong (王亦忠) Acta Physica Sinica (Overseas Edition), 1995, 4 (12):  912-916.  DOI: 10.1088/1004-423X/4/12/005 Abstract ( 1351 )   PDF (149KB) ( 338 )   ErFe11.35Nb0.65 AND ErFe11.35Nb0.65Ny have been synthesized and neutron-powder-diffraction experiments at room temperature performed. The ErFe11.35Nb0.65Ny nitride, obtained by gas-solid reaction, retains the ThMn12-type structure of its parent compound. The Nb atoms occupy 8i sites and the nitrogen atoms are located at 2b sites. The atomic magnetic moments of the Er ions are antiparallel to those of the Fe atoms. Upon nitrogenation, the lattice cell expands mainly along the a-axis and the atomic magnetic moments of Fe are enhanced.

CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES

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STUDIES ON THE NEXT-NEAREST NEIGHBOR HOPPING INTERACTIONS OF $\pi$-ELECTRONS IN QUASI-ONE-DIMENSIONAL ORGANIC FERROMAGNETIC MODEL FANG ZHONG (方忠), Liu Zu-li (刘祖黎), YAO KAI-LUN (姚凯伦), LI ZAI-GUANG (李再光) Acta Physica Sinica (Overseas Edition), 1995, 4 (12):  917-922.  DOI: 10.1088/1004-423X/4/12/006 Abstract ( 1024 )   PDF (172KB) ( 418 )   Based on a theoretical model proposed for quasi-one-dimensional organic polymer fer-romagnets, the next-nearest neighbor hopping interactions of $\pi$-electrons are considered. Allowing for full lattice relaxation, a set of self-consistent equations is established to study the system. The spin-density-wave (SDW) and the possible ferromagnetic ground state of the system are investigated in detail. It is found that the next-nearest neighbor hopping in-teractions will make the SDW stronger and consequently make the ferromagnetic state more stable as compared with the nonmagnetic reference state.

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THEORETICAL AND EXPERIMENTAL INVESTIGATION ON ANOMALOUS HALL EFFECT OF HETEROGENOUS SEMICONDUCTOR SAMPLES JIANG WEI (姜伟), Lu Gang (鲁刚), Song Lu-wu (宋录武) Acta Physica Sinica (Overseas Edition), 1995, 4 (12):  923-932.  DOI: 10.1088/1004-423X/4/12/007 Abstract ( 1109 )   PDF (239KB) ( 360 )   Based on the theoretical results of inversion layers model and interpenetrating network model, we studied the anomalous Hall effect of heterogenous semiconductor samples, and obtained the following results: (1) the wider the sample energy gap, the higher the temper-ature at which anomalous Hall effect begins to appear; (2) the lower the sample resistivity, the higher the temperature at which anomalous Hall effect begins to appear, which is further verified in our experiment; (3) mobility is the main factor which determines what role p-n junction plays in sample Hall voltage; (4) for n-Ge sample with inversion layers structure, with the increase of p-type region, the Hall effect changes from normal n-type Hall effect to anomalous Hall effect of the single dip type, then to anomalous Hall effect of the second reversal type.