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Damage produced on GaN surface by highly charged Krq+irradiation

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Nuclear Science and Techniques 2017年第12期28卷 220-225页

作者： Li-Qing Zhang Chong-Hong Zhang Chao-Liang Xu Heng-Qing Zhang Yi-Tao Yang Jin-Yu Li Hui-Ping Liu Zhao-Nan Ding Ting-Xing Yan Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Surface morphology, compositions, microstructure and optical properties of GaN film irradiated by highly charged Kr^(q+)(q = 23, 15, 11) in two geometries to a fluence of 1×10^(15)kr^(q+)/cm^2 were studied using AFM,XPS, PL, Raman scattering and UV–visible *** AFM observation shows that the irradiated GaN area is a swollen terrace. The swelling rate increased with the charge state(potential energy). For the same charge state,the swelling rate of tilted incidence was greater than that for normal incidence. The XPS measurements reveal that N deficiency, Ga enrichment and Ga–O and Ga dangling bonds generated on the irradiated GaN surface increased with the charge state, and more N was lost for normal incidence than that for tilted incidence. The UV–Vis results show that the transmittance decreased with increasing charge state. For the same charge state, the transmittance for tilted incidence is higher than that for normal *** PL spectra present that, with increasing charge state,the YL band intensity decreased, with a blueshift in its peak position; while the NBE peak intensity increased firstand then reduced, and a blue luminescence band appeared.A rapid quenching of both the YL and the NEB for normal incidence was observed. Raman spectra display that screw dislocations perhaps were produced near the surface for normal incidence.

关键词： GaN Highly charged Krypton ion AFM XPS UV–Vis transmittance spectra PL Raman spectra

Multiply charged Anions,Maximum Charge Acceptance,and Higher Electron Affinities of Molecules,Superatoms,and Clusters

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物理化学学报 2018年第6期34卷 675-682页

作者： VON SZENTPáLY László Institut fur Theoretische Chemie Universitat Stuttgart Pfaffenwaldring 55 70569 Stuttgart Germany.

The addition of electrons to form gas-phase multiply charged anions(MCAs)normally requires sophisticated experiments or *** this work,the factors stabilizing the MCAs,the maximum electron uptake of gas-phase molecules,X,and the electronic stability of MCAs X^(Q-),are *** drawbacks encountered when applying computational and/or conceptual density functional theory(DFT)to MCAs are *** develop and test a different model based on the valence-state *** in DFT,the electronic energy,E(N,v_(ex)),is a continuous function of the average electron number,N,and the external potential,v_(ex),of the *** valence-state-parabola is a second-order polynomial that allows extending E(N,v_(ex))to dianions and higher *** model expresses the maximum electron acceptance,Q_(max),and the higher electron affinities,A_Q,as simple functions of the firstelectron affinity,A_1,and the ionization energy,I,of the"ancestor"***,the maximum electron acceptance is Q_(max,calc)=1+12A_1/7(I-A_1).The ground-state parabola model of the conceptual DFT yields approximately half of this value,and it is termed Q_(max,GS)=?+A_1/(I-A_1).A large variety of molecules are evaluated including fullerenes,metal clusters,super-pnictogens,super-halogens(OF_3),super-alkali species(OLi_3),and neutral or charged transition-metal complexes,AB_(m )L_n^(0/+/-).The calculated second electron affinity A_(2,calc)=A_1-(7/12)(I-A_1)is linearly correlated to the literature references A_(2,lit) with a correlation coefficient R=0.998.A_2 or A_3 values are predicted for further 24 *** appearance sizes,n_(ap)^(3-),of triply charged anionic clusters and fullerenes are calculated in agreement with the literature.

关键词： Multiply charged negative ions Their appearance sizes Second electron affinity Third electronaffinity Conceptual density-functional theory Valence-state parabola model of electronegativity

Fast Computation of Electrostatic Interactions for a charged Polymer with Applied Field

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高分子科学：英文版 2020年第6期38卷 665-672页

作者： Hao Lin Zi-Tong Lei Ming-Ming Ding Hong-Jun Wang Tong-Fei Shi School of Mathematics Jilin Normal UniversityChangchun 130103China State Key Laboratory of Polymer Physics and Chemistry Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 730022China College of Computer Jilin Normal UniversitySi ping 136000China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China

Using a hybrid simulation approach that combines a finite difference method with a Brownian dynamics,we investigated the motion of charged *** to the fact that polymer-solution systems often contain a large number of particles and the charged palymer chains are in a state of random motion,it is a time consuming task to calculate the electrostatic interaction of the ***,we propose a new strategy to shorten the CPU time by reducing the iteration *** simulation results ilustrate the effect of preset parameters on CPU time and accuracy,and demonstrate the feasibility of the"local iteration"***,we find that the increase in the number of charged beads has no signifiant infuence on the time of global iterations and local *** a number of 80×80×80 grids,when the relative error is controlled below 1.5%,the computational efficiency is increased by 8.7 times in the case that contains 500 charged *** adition,for a number of 100×100×100 grids with 100 charged beads,the computational efciency can be increased up to 12 *** work provides new insights for the optimization of iterative algorithms in special problems.

关键词： Finite dfference method Brownian dynamics charged polymers Electrostatic interaction Local iteration

Electromagnetic scattering of charged particles in a strong wind-blown sand electric field

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Chinese Physics B 2019年第3期28卷 218-222页

作者： Xingcai Li Xuan Gao Juan Wang School of Physics and Electronic-Electrical Engineering Ningxia UniversityYinchuan 750021China Ningxia Key Laboratory of Intelligent Sensing for the Desert Information Ningxia UniversityYinchuan 750021China Xinhua College Ningxia UniversityYinchuan 750021China

Some field experimental results have shown that the moving sands or dust aerosols in nature are usually electrified,and those charged particles also produce a strong electric field in air, which is named as wind-blown sand electric *** scholars have pointed out that the net charge on the particle significantly enhances its electromagnetic(EM) extinction properties, but up to now, there is no conclusive research on the effect of the environmental electric field. Based on the extended Mie theory, the effect of the electric field in a sandstorm on the EM attenuation properties of the charged larger dust particle is studied. The numerical results indicate that the environmental electric field also has a great influence on the particle's optical properties, and the stronger the electric field, the bigger the effect. In addition, the charged angle, the charge density, and the particle radius all have a specific impact on the charged particle's optical properties.

关键词： wind-blown sand electric field extended Mie theory charged particle scattering

X-ray spectra induced by slow highly charged Ar^(q+) ions in collision with Nb surface

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Science China(Physics,Mechanics & Astronomy) 2008年第10期51卷 1463-1469页

作者： YANG ZhiHu1, CUI Ying2, CHEN XiMeng2, SONG ZhangYong1, SHAO JianXiong2, RUAN FangFang1, ZHANG HongQiang2, DU Juan2, LIU YuWen2, GAO ZhiMing2, ZHANG XiaoAn3, ZHU KeXin1, YU DeYang1 & CAI XiaoHong1 1 Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China 2 Department of Modern Physics, Lanzhou University, Lanzhou 730000, China 3 Department of Physics, Xianyang Normal College, Xianyang 712000, China Institute of Modern Physics Chinese Academy of Sciences Lanzhou China Department of Modern Physics Lanzhou University Lanzhou China Department of Physics Xianyang Normal College Xianyang China

The X-ray spectra of Nb surface induced by Arq+ (q =16,17) ions with the energy range from 10 to 20 keV/q were studied by the optical spectrum technology. The experimental results indicate that the multi-electron excitation occurred as a highly charged Ar16+ ion was neutralized below the metal surface. The K shell electron of Ar16+ was excited and then de-excited cascadly to emit K X-ray. The intensity of the X-ray emitted from K shell of the hollow Ar atom decreased with the increase of projectile kinetic energy. The intensity of the X-ray emitted from L shell of the target atom Nb increased with the increase of projectile kinetic energy. The X-ray yield of Ar17+ is three magnitude orders larger than that of Ar16+.

关键词： highly charged ion hollow atom multi-electron X-ray

Trapping and Driving Individual charged Micro-particles in Fluid with an Electrostatic Device

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Nano-Micro Letters 2016年第3期8卷 270-281页

作者： Jingjing Xu Zijing Lei Jingkun Guo Jie Huang Wei Wang Uta Reibetanz Shengyong Xu Key Laboratory for the Physics & Chemistry of Nanodevices and Department of Electronics Peking University Institute of Microelectronics Peking University Medical Faculty Institute for Medical Physics and Biophysics University of Leipzig

A variety of micro-tweezers techniques, such as optical tweezers, magnetic tweezers, and dielectrophoresis technique, have been applied intensively in precise characterization of micro/nanoparticles and bio-molecules. They have contributed remarkably in better understanding of working mechanisms of individual sub-cell organelles, proteins, and DNA. In this paper, we present a controllable electrostatic device embedded in a microchannel, which is capable of driving,trapping, and releasing charged micro-particles suspended in microfluid, demonstrating the basic concepts of electrostatic tweezers. Such a device is scalable to smaller size and offers an alternative to currently used micro-tweezers for application in sorting, selecting, manipulating, and analyzing individual micro/nanoparticles. Furthermore, the system offers the potential in being combined with dielectrophoresis and other techniques to create hybrid micro-manipulation systems.

关键词： Electrostatic tweezers charged particles Coulomb potential well Manipulation Trap

Generation of multiple charged ions: Photoemission electron impact ionization

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Science China Chemistry 1998年第5期41卷 525-534页

作者：王利李海洋白吉玲吕日昌 State Key Laboratory of Molecular Reaction Dynamics Dalian Institute of Chemical Physics Dalian China

Delayed pulsed electric field was used to investigate the generation mechanism of multiple charged ions produced in the interaction of laser, metal surface and electric field on time_of_flight mass spectrometer (TOF MS). A special photoelectron generator was designed to control the energy and timing of the photoelectron beam. This modification made it possible to separate the photoionization process from photoelectron impact ionization. The experiment showed that the multiple charged ions could be produced only by the photoelectron impact, ionized step by step. A design of dual ionization configuration was presented, which could be used to study either multiphoton ionization or photoemission electron impact ionization.

关键词： multiple charged ions photoemission electron electron impact ionization time_of_flight mass spectrometer.

Effects of charged sand on electromagnetic wave propagation and its scattering field

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Science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 77-87页

作者： HE Qinshu ZHOU Youhe ZHENG Xiaojing Department of Mechanics Lanzhou University Gansu 730000 China Department of Mechanics Lanzhou University Gansu 730000 China Department of Mechanics Lanzhou University Gansu 730000 China

Based on the Rayleigh’s scattering theory, the effects of sandstorms on the propagation of electromagnetic wave with different visibilities are presented by solving the scattering field of charged sand particles. Because of the electric charges on the sand surface, the theoretical attenuation will be large enough to match the measured value under certain conditions. And the results show that the effect of sand with electric charges all over its surface on electromagnetic wave attenuation is the same as that of sand without charge, which proves that electric charges distribute on partial surface of the sand in fact.

关键词： scattering field, electromagnetic waves attenuation, wind-blown sand transport, charged sand.

X-ray spectra induced in highly charged 40Ar^q+ interacting with Au surface

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Science China(Physics,Mechanics & Astronomy) 2006年第2期49卷 203-212页

作者： ZHANG Xiao’an1,2, XIAO Guoqing1, YANG Zhihu1, CHEN Ximeng3, ZHAO Yongtao1, LI Fuli4, ZHANG Yinping1, CUI Ying3, ZHANG Hongqiang3, XU Xu3, SHAO Jianxiong3 & ZHAN Wenlong11. Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000, China 2. Department of Physics, Xianyang Normal University, Xianyang 712000, China 3. Department of Modern Physics, Lanzhou University, Lanzhou 730000, China 4. Department of Applied Physics, Xi’an Jiaotong University, Xi’an 710049, China Institute of Modern Physics Chinese Academy of Sciences Lanzhou China Department of Physics Xianyang Normal University Xianyang China Department of Modern Physics Lanzhou University Lanzhou China Department of Applied Physics Xi’an Jiaotong University Xi’an China

By use of optical spectrum technology, the spectra of X-ray induced by highly charged 40Arq+ ions interacting with Au surface have been studied. The results show that the argon Kα X-ray were emitted from the hollow atoms formed below the surface. There is a process of multi-electron exciting in neutralization of the Ar16+ion, with electronic con-figuration 1s2 in its ground state below the solid surface. The yield of the projectile Kα X-ray is related to its initial electronic configuration, and the yield of the target X-ray is related to the projectile kinetic energy.

关键词： highly charged ion hollow multi-electron excitation X- ray.