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Combined multi-level quantum mechanics theories and molecular mechanics study of water-induced transition state of OH^- + CO_2 reaction in aqueous solution

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Chinese physics B 2017年第10期26卷 200-204页

作者：李琛牛美兴刘鹏李永方王敦友 College of Physics and Electronics Shandong Normal University

The presence of a solvent interacting with a system brings about qualitative changes from the corresponding gas-phase reactions. A solvent can not only change the energetics along the reaction pathway, but also radically alter the reaction mechanism. Here, we investigated the water-induced transition state of the OH^-＋CO2→HCO3^- reaction using a multi-level quantum mechanics and molecular mechanics method with an explicit water model. The solvent energy contribution along the reaction pathway has a maximum value which induces the highest energy point on the potential of mean force. The charge transfer from OH^- to CO2 results in the breaking of the OH^- solvation shell and the forming of the CO2 solvation shell. The loss of hydrogen bonds in the OH^- solvation shell without being compensated by the formation of hydrogen bonds in the CO2 solvation shell induces the transition state in the aqueous solution. The calculated free energy reaction barrier at the CCSD（T）/MM level of theory, 11.8 kcal/mol, agrees very well with the experimental value, 12.1 kcal/mol.

关键词： transition state reaction pathway free energy barrier solvent effect

Analysis of the fractal intrinsic quality in the ionization of Rydberg helium and lithium atoms

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Chinese physics B 2018年第5期27卷 166-171页

作者：张延惠徐秀兰康丽莎蔡祥吉唐旭 College of Physics and Electronics Shandong Normal University School of physics Shandong University

We study the fractal rhythm in the ionization of Rydberg helium and lithium atoms in an electric field by using the semiclassical method. The fractal structures present a nested relationship layer by layer in the initial launch angles of the ionized electrons versus the escape time, which is defined as the rhythm attractor, and exhibit similar rhythm endings. The gradually enhanced chaotic regions of the escape time plots tend to broaden as the scaled energy increases. In addition,the fractal rhythm changes synchronously with the oscillations of the kinetic energy spectrum. We note that the intrinsic quality of the fractal rhythm is closely related to the kinetic energy distribution, that is, the inherent dynamic properties of the Hamiltonian equations have an impact on the fractal regularities. In addition, different ionizing closed trajectories exhibit iterate properties and the inherent beauty of symmetry. Our results and analysis can not only reveal new laws in the ionization of Rydberg atoms, but also promote the establishment of the dynamic mechanism of fractals.

关键词： ionization dynamics Rydberg atoms fractal rhythm kinetic energy spectrum

Tunneling dynamics of bosons in the diamond lattice chain

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Chinese physics B 2018年第10期27卷 440-448页

作者：常娜娜薛具奎 College of Physics and Electronics Engineering Northwest Normal University

We analyze the effect of tilting and artificial magnetic flux, on the energy bands structure for the system and the corresponding tunneling dynamics for bosons with various initial configurations in the diamond lattice chain, where intriguing and significant phenomena occur, including Landau–Zener tunneling, Bloch oscillations, and localization phenomenon.Both vertical tilting and artificial magnetic flux may alter the structure of energy levels（dispersion structure or flat band）,and enforce the occurrence of Landau–Zener tunneling, which scans the whole of the Bloch bands. We find that, transitions among Landau–Zener tunneling, Bloch oscillations, and localization phenomenon, are not only closely related to the energy bands structure, but also depends on the initial configuration of bosons in the diamond lattice chain. As a consequence,Landau–Zener tunneling, Bloch oscillations, and localization phenonmenon of bosons always counteract and are complementary with each other in the diamond lattice chain.

关键词： Bose-Einstein condensate Landau-Zener tunneling Bloch oscillation localization flat band

Wakefield generation by chirped super-Gaussian laser pulse in inhomogeneous plasma

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Plasma Science and Technology 2018年第11期20卷 28-36页

作者：姚征伟成丽红唐荣安薛具奎 College of Physics and Electronics Engineering Northwest Normal University

We study the effect of nonlinearly chirped super-Gaussian （SG） laser pulse on wakefield generation in an inhomogeneous plasma. The different types of nonlinearly chirped pulse are employed, and different kinds of inhomogeneous plasma density are used. The maximum wakefield amplitude as the function of nonlinearly chirped laser pulse and inhomogeneous plasma density in parameter space are obtained. Moreover, the dependence of the maximum wakefield amplitude on the SG laser pulse index is discussed. This shows that a larger wakefield can be obtained when the chirped pulse and inhomogeneous density are in the critical regions. Wakefield generation can be controlled by adjusting the chirped SG pulse and inhomogeneous plasma density parameters. That is, we provide an efficient way for the controlled generation of the wakefield.

关键词： laser-plasma interaction inhomogeneous plasma plasma wakefield

Spontaneous emission in the optically excited single-electron-tunneling device tuned by the tunneling

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Chinese Optics Letters 2014年第11期12卷 94-98页

作者：李荣华张森阎维贤 College of Physics and Electronics Shanxi University

The spontaneous emission spectrum in the optically excited single-electron-tunneling device coupled to the side dot is analytically found to be determined by the 12 exciton-complex optical channels with different optical weight functions. The electronic tunneling channels and optical transition channels co-determine the emission, where the competition between the electron-like and hole-like channels leads to the tail effect and the competition between the lower and higher energy resonant optical channels leads to the blueshift（redshift） of the emission signal.

关键词： Emission spectroscopy Spontaneous emission

Relative carrier-envelope phase dependence of resonant propagation of two-colour femtosecond pulses in V-type atomic medium

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Chinese physics B 2010年第6期19卷 349-355页

作者：谭霞王振东王蕾樊锡君 College of Physics and Electronics Shandong Normal University College of Physics and Electronics Weifang University

Using numerical solution of the full Maxwell-Bloch equations, which is obtained by the finite-difference time-domain method and the iterative predictor-orrector method, we investigate the modulation effect of relative carrierenvelope phase （hereinafter referred to as the relative phase） on resonant propagation of two-colour femtosecond ultrashort laser pulses in a V-type three-level atomic medium. It is found that the pulse splitting occurs for a smaller value of relative phase; when the value of relative phase increases to a certain value, only the variation of pulse shape is present and the pulse splitting does not occur any more; moreover, when the value of relative phase is smaller, the pulse group velocity is larger. The relative phase also has an obvious effect on population and spectral property. Different population transfers can be realized by adjusting the value of relative phase. Generally speaking, for the pulses with smaller areas their spectral strengths and frequency ranges decrease obviously with the value of relative phase increasing; for the pulses with larger areas, with value of the relative phase increasing, their spectral strengths decrease remarkably but the relative strengths of the higher frequency components increase significantly, while the spectral frequency range is not varied evidently.

关键词： two-colour ultrashort pulses relative carrier envelope phase resonant propagation V- type three-level atomic medium

Generation of arbitrary vector beams based on a single spatial light modulator and a thin-film polarization splitting cubic

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Chinese Optics Letters 2016年第12期14卷 117-121页

作者：谢一言杨杨韩璐岳庆炀国承山 College of Physics and Electronics Shandong Normal University

A setup for the generation of arbitrary vector beams is proposed. The setup mainly consists of a spatial light modulator（SLM）, an angle-adjustable polarization beam splitter modulator, and a spatial filtering imaging system. Compared with the system using a birefringent beam splitter with a non-adjustable splitting angle,the polarization splitting angle of the improved setup can be adjusted by slightly rotating the related mirrors,which will bring more convenience when different wavelengths and different pixel sizes of SLMs are involved.The experimental results also demonstrate that the setup possesses a good polarization-selective imaging ability, which reveals that the setup may also be useful in polarization-selective spatial filtering imaging and polarization-encoded encryption.

关键词： modulator splitter arbitrary mirrors adjustable filtering pixel setup cubic rotating

Responsive mechanism of 2-(2'-hydroxyphenyl)benzoxazole-based two-photon fluorescent probes for zinc and hydroxide ions

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Chinese physics B 2015年第2期24卷 122-127页

作者：张玉瑾张秋月丁红娟宋秀能王传奎 College of Physics and Electronics Shandong Normal University

Response theory is used to investigate one- and two-photon absorption（TPA） as well as the emission properties of a series of potential zinc ion and pH sensitive materials containing 2-（2＇-hydroxyphenyl）benzoxazole（HPBO） end groups.Special emphasis is placed on the evolution of their optical properties upon combining with zinc ions or deprotonation.Our calculated results indicate that upon combining with zinc ions or deprotonation,these HPBO derivatives show drastic changes in their one-photon absorption（OPA）,emission,and TPA properties.Moreover,the mechanisms of the probes are analyzed and found to be an intramolecular charge transfer.These compounds are thus proved to be excellent candidates for two-photon fluorescent zinc and pH probes.

关键词： two-photon absorption response theory zinc probe pH probe

Effect of interfacial coupling on rectification in organic spin rectifiers

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Chinese physics B 2015年第7期24卷 468-474页

作者：胡贵超左梦莹李营张朝任俊峰王传奎 College of Physics and Electronics Shandong Normal University

The effect of interfacial coupling on rectification in an organic co-oligomer spin diode is investigated theoretically by considering spin-independent and spin-resolved couplings respectively. In the case of spin-independent coupling, an optimal interfacial coupling strength with a significant enhanced rectification ratio is found, whose value depends on the structural asymmetry of the molecule. In the case of spin-resolved coupling, we found that only the variation of the interfacial coupling with specific spin is effective to modulate the rectification, which is due to the spin-filtering property of the central asymmetric magnetic molecule. A transition of the spin-current rectification between parallel spin-current rectification and antiparallel spin-current rectification may be observed with the variation of the spin-resolved interfacial coupling. The interfacial effect on rectification is further analyzed from the spin-dependent transmission spectrum at different biases.

关键词： organic spintronics,organic ferromagnet,rectification,interfacial coupling