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AbstractAbstract

[en] Highlights: • The photodetachment of H"− in an oscillating electric field has been studied using the time-dependent closed orbit theory. • An analytical formula for calculating the photodetachement cross section has been put forward. • Our study provides a clear physical picture for the photodetachment of negative ion in an oscillating electric filed. • Our work is useful in guiding the experimental research for the photodetachment dynamics in the time-dependent field. - Abstract: Using the time-dependent closed orbit theory, we study the photodetachment of H"− ion in a time-dependent electric field. The photodetachment cross section is specifically studied in the presence of a static electric field plus an oscillating electric field. We find that the photodetachment of negative ion in the time-dependent electric field becomes much more complicated than the case in a static electric field. The oscillating electric field can weaken the photodetachment cross section greatly when the strength of the oscillating electric field is less than the static electric field. However, as the strength of the oscillating electric field is larger than the static electric field, four types of closed orbits are identified for the detached electron, which makes the oscillating amplitude in the photodetachment cross section gets increased again. The connection between the detached electron’s closed orbit with the oscillating cross section is analyzed quantitatively. This study provides a clear and intuitive picture for the understanding of the connections between quantum and classical description for the time-dependent Hamiltonian systems and may guide the future experimental research for the photodetachment dynamics in the time-dependent electric field.

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S0368-2048(16)30103-7; Available from http://dx.doi.org/10.1016/j.elspec.2016.12.003; Copyright (c) 2016 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)

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Journal Article

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Journal of Electron Spectroscopy and Related Phenomena; ISSN 0368-2048; ; CODEN JESRAW; v. 214; p. 20-28

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AbstractAbstract

[en] Highlights: •On the basis of the semiclassical theory, the photodetachment electron flux of H

^{−}in combined electric field and magnetic field with arbitrary orientation has been studied for the first time. •Our calculation results suggest that the electron flux distributions on the detector plane is not only related to the angle between the electric and magnetic fields, but also related to the electron energy. •Our studies may guide the future experimental researches in the photodetachment microscopy of some more complex negative ions in the presence of external fields. -- Abstract: On the basis of the semi-classical theory, we calculate the photodetachment electron flux of H^{−}in combined electric field and magnetic field with arbitrary orientation. Our results suggest that the electron flux distributions on the detector plane is not only related to the angle between the electric and magnetic fields, but also related to the electron energy. With the increase of the angle between the electric and magnetic field, the oscillating region in the electron flux distributions becomes smaller. In addition, we find with the increase of the detached electron's energy, the oscillating structure in the flux distributions becomes much more complicated. Therefore, the oscillation in the detached electron flux distributions can be controlled by adjusting the angle between the electric and magnetic field and the detached electron's energy. We hope that our studies may guide the future experimental researches in the photodetachment microscopy of negative ion in the presence of external fieldsSource

S0368-2048(13)00131-X; Available from http://dx.doi.org/10.1016/j.elspec.2013.08.001; Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)

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Journal Article

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Journal of Electron Spectroscopy and Related Phenomena; ISSN 0368-2048; ; CODEN JESRAW; v. 189; p. 96-102

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Liu, Sheng; Wang, De-hua, E-mail: lduwdh@163.com

AbstractAbstract

[en] When a laser is irradiated on a negative ion, it will provide a coherent, mono-energetic source of detached electrons propagating out from the location of the negative ion. The total escape probability density of the electrons when the negative ion is placed inside an open nano-circular microcavity has been studied on the basis of the semiclassical theory. It is shown that significant oscillations appear in the total escape probability density due to the quantum interference effects. Besides, our study suggests that the escape probability density depends on the laser polarization sensitively. In order to show the correspondence between the escaped probability density and the detached electron's escaped orbits clearly, we calculate the path length spectrum and find that each peak corresponds to the length of one detached electron's escaped orbit. This study provides an example where the quantum nature of the electron's wave function can be observed in the macroscopic world. Our study may guide the future experimental research on the escape and transport process of particles through semiconductor microjunctions.

Source

S0921-4526(14)00139-2; Available from http://dx.doi.org/10.1016/j.physb.2014.02.044; Copyright (c) 2014 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)

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Journal Article

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Wang, De-hua; Chen, Qiang; Xu, Qin-feng, E-mail: lduwdh@163.com

AbstractAbstract

[en] Highlights: • The photodetachment of H

^{−}ion near two repulsive centers has been studied using the COT theory. • Our study suggests that the photodetachment cross section exhibits multi-periodic oscillatory structure. • Each peak in the Fourier transformed cross section corresponds to the scaled action of one detached electron's closed orbit. • Our study may guide the experimental researches in the photodetachment of multiply charged anions. - Abstract: Based on a theoretical model for the photodetachment of negative ion near a repulsive center, we study the photodetachment of H^{−}ion near two repulsive centers. Using the semiclassical closed orbit theory, we study the classical motion of the detached electron and calculate the photodetachment cross section of H^{−}ion near two repulsive centers. It is found that the repulsive centers have significant effects on the photodetachment of H^{−}ion. The photodetachment cross section of our system is strongly oscillatory compared to the photodetachment near one repulsive center. The calculation results suggest: if one repulsive center is kept fixed, with the decrease of the distance between two repulsive centers, the oscillating amplitude in the cross section becomes enlarged and the photodetachment cross section exhibits a multi-periodic oscillatory structure. In order to show the correspondence between the oscillation in the photodetachment cross section and the detached electron's classical closed orbits clearly, we make a Fourier transformation for the scaled photodetachment cross section of this system. Each peak in the Fourier transformed cross section corresponds to the scaled action of one closed orbit. We hope that our study will be useful in directing the future experimental research of the photodetachment processes of multiply charged anionsPrimary Subject

Source

S0368-2048(13)00238-7; Available from http://dx.doi.org/10.1016/j.elspec.2013.12.003; Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: Austria

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Journal Article

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Journal of Electron Spectroscopy and Related Phenomena; ISSN 0368-2048; ; CODEN JESRAW; v. 192; p. 75-82

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AbstractAbstract

[en] The ionisation of Rydberg helium atoms in an electric field above the classical ionisation threshold has been examined using the semiclassical method, with particular emphasis on discussing the influence of the core scattering on the escape dynamics of electrons. The results show that the Rydberg helium atoms ionise by emitting a train of electron pulses. Unlike the case of the ionisation of Rydberg hydrogen atom in parallel electric and magnetic fields, where the pulses of the electron are caused by the external magnetic field, the pulse trains for Rydberg helium atoms are created through core scattering. Each peak in the ionisation rate corresponds to the contribution of one core-scattered combination trajectory. This fact further illustrates that the ionic core scattering leads to the chaotic property of the Rydberg helium atom in external fields. Our studies provide a simple explanation for the escape dynamics in the ionisation of nonhydrogenic atoms in external fields. (atomic and molecular physics)

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Available from http://dx.doi.org/10.1088/1674-1056/20/1/013403; Country of input: International Atomic Energy Agency (IAEA)

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Journal Article

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Chinese Physics. B; ISSN 1674-1056; ; v. 20(1); [5 p.]

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AbstractAbstract

[en] We study the photodetachment dynamics of H

^{−}ion in the time-dependent oscillating electric and magnetic fields for the first time. The wave function of the detached electron at a given point on the detector plane is constructed using the semiclassical method, which is related to the electron trajectories in the oscillating electric and magnetic fields. It is found due to the interplay of the time-dependent oscillating electric and magnetic fields, multiple electron trajectories emitted from the negative ion source can arrive at a given detector point. The interference between these electron trajectories causes the oscillatory structures in the electron probability density. Modifications of electron probability density caused by different oscillating electric and magnetic fields and the position of the detector plane are also studied and explained. It is shown that even at a macroscopic distance from the negative ion source, the interference patterns in the electron probability density can be seen clearly, which can be realized in an actual photodetachment experiment. Therefore, our work can serve as a guide for the future experimental studies of the photodetachment of negative ions in the oscillating electric and magnetic fields. (author)Primary Subject

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Journal Article

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Indian Journal of Physics (Online); ISSN 0974-9845; ; v. 93(2); p. 243-250

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Wang, De-hua; Sun, Xin-yue; Shi, Tong, E-mail: jnwdh@sohu.com

AbstractAbstract

[en] Photodetachment dynamics of negative ions near a moving surface is investigated for the first time. An analytical formula for the photodetachment cross section of negative ions induced by the moving surface has been put forward. This formula is universal and appropriate to any negative ion no matter the photodetachment is dominated by an

*s*-wave source or a*p*-wave source. In contrast to the photodetachment of negative ion near a static surface, the returning kinetic energy of the detached electron is different from its initial value after it is bounced back by the moving surface; therefore, an additional modulation function related to the electron’s initial and returning momentum is multiplied in the oscillating cross section. As a demonstration, we calculate the photodetachment cross section of H^{−}and Cl^{−}ions near a moving surface. It is shown that the photodetachment cross section depends on the electron’s energy and the speed of the moving surface sensitively. Therefore, we can control the photodetachment dynamics of negative ion by a moving surface. Our work provides some insights into the behavior of photodetachment dynamics of negative ion near a moving surface and may guide the future experiments toward this field. Graphical abstract:.

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Copyright (c) 2019 EDP Sciences, SIF, Springer-Verlag GmbH Germany, part of Springer Nature; Country of input: International Atomic Energy Agency (IAEA)

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Journal Article

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European Physical Journal. D, Atomic, Molecular and Optical Physics; ISSN 1434-6060; ; v. 73(1); p. 1-10

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AbstractAbstract

[en] According to the closed-orbit theory, we study the influence of elastic interface on the photodetachment of H

^{−}near a metallic sphere surface. First, we give a clear physical description of the detached electron movement between the elastic interface and the metallic sphere surface. Then we put forward an analytical formula for calculating the photodetachment cross section of this system. Our study suggests that the photodetachment cross section of H^{−}is changed with the distance between the elastic interface and H^{−}. Compared with the photodetachment cross section of H^{−}near a metallic sphere surface without the elastic interface, the cross section of our system oscillates and its oscillation is strengthened with the decrease of the distance from the elastic interface to H^{−}. In additon, our calcuation results suggest that the influence of the elastic interface becomes much more significant when it is located in the lower half space rather than in the upper half space. Therefore, we can control the photodetachment of H^{−}near a metallic sphere surface by changing the position of the elastic interface. We hope that our work is conducive to the understanding of the photodetachment process of negative ions near interfaces, cavities and ion traps. (atomic and molecular physics)Primary Subject

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Available from http://dx.doi.org/10.1088/1674-1056/23/2/023402; Country of input: International Atomic Energy Agency (IAEA)

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Journal Article

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Chinese Physics. B; ISSN 1674-1056; ; v. 23(2); [8 p.]

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AbstractAbstract

[en] This paper investigates the escape of photodetached electron from a nanocircular microcavity on the basis of the semiclassical theory. The escaped orbit of the photodetached electron is investigated and the escaped probability density of this system is derived and calculated. The calculation results suggest that oscillating structures appear in the escaped probability density, which are caused by the interference effects of the electron waves traveling along different escaped trajectories. Our study also suggests that the escaped probability density of the photodetached electron depends on the laser polarization sensitively. To show the correspondence between the escaped probability density and the detached electron's escaped orbits clearly, we calculate the Fourier transform of the semiclassical wave function and find each peak corresponds to the length of one detached electron's orbit. We hope that our results will be useful in understanding the escape and transport process of particles through semiconductor microjunctions. (author)

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Available from doi: http://dx.doi.org/10.1139/cjp-2013-0332; 27 refs., 1 tab., 5 figs.

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Journal Article

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Canadian Journal of Physics; ISSN 0008-4204; ; v. 91(10); p. 808-814

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AbstractAbstract

[en] In this paper, we investigate the photoionization microscopy of the Rydberg hydrogen atom in a gradient electric field for the first time. The observed oscillatory patterns in the photoionization microscopy are explained within the framework of the semiclassical theory, which can be considered as a manifestation of interference between various electron trajectories arriving at a given point on the detector plane. In contrast with the photoionization microscopy in the uniform electric field, the trajectories of the ionized electron in the gradient electric field will become chaotic. An infinite set of different electron trajectories can arrive at a given point on the detector plane, which makes the interference pattern of the electron probability density distribution extremely complicated. Our calculation results suggest that the oscillatory pattern in the electron probability density distribution depends sensitively on the electric field gradient, the scaled energy and the position of the detector plane. Through our research, we predict that the interference pattern in the electron probability density distribution can be observed in an actual photoionization microscopy experiment once the external electric field strength and the position of the electron detector plane are reasonable. This study provides some references for the future experimental research on the photoionization microscopy of the Rydberg atom in the non-uniform external fields. (paper)

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Available from http://dx.doi.org/10.1088/1674-1056/25/6/063201; Country of input: International Atomic Energy Agency (IAEA)

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Journal Article

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Chinese Physics. B; ISSN 1674-1056; ; v. 25(6); [10 p.]

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