Time-dependent electric field effect on the photodetachment dynamics of negative ions

2017 ◽  
Vol 95 (5) ◽  
pp. 507-513 ◽  
Author(s):  
De-hua Wang
Keyword(s):  
Electric Field ◽  
Probability Density ◽  
External Electric Field ◽  
Negative Ions ◽  
Time Dependent ◽  
Negative Ion ◽  
Electric Field Effect ◽  
Electron Trajectories ◽  
Oscillatory Pattern ◽  
Electron Probability Density

This paper addresses the photodetachment dynamics of a negative ion in a time-dependent electric field based on the semiclassical open-orbit theory. The photodetached electron probability density in a real time domain is studied in a gradient electric field for the first time. It is found that because of the influence of the gradient electric field, two or more electron trajectories can arrive at a given point on the detector, and the interference effect between these electron trajectories causes oscillatory structures in the electron probability density. Our calculation results suggest that when the external electric field changes very slowly with time, only two electron trajectories can arrive at a given point on the detector and the electron probability density exhibits a regular two-term oscillatory pattern. However, when the electric field changes quickly with time, four electron trajectories can reach the detector, which makes the oscillatory structures in the electron probability density become much more complicated. In addition, the electric field strength, photon energy, and the position of the detector can affect the electron probability density of this system sensitively. Our study provides a clear and intuitive picture for the photodetachment dynamics of the negative ion in the external electric field from a time-dependent viewpoint and may guide the future experimental researches on the photodetachment microscopy of negative ions in the time-dependent electric field.

Oxygen migration and optical properties of coronene oxides and their persulfurated derivatives: insight into the electric field effect and the oxygen-site dependence

2020 ◽  
Vol 22 (35) ◽  
pp. 20078-20086
Author(s):  
Qing Zhang ◽  
Yuanyuan Li ◽  
Zexing Cao
Keyword(s):  
Optical Properties ◽  
Electric Field ◽  
External Electric Field ◽  
Field Effect ◽  
Electric Field Effect ◽  
Oxygen Migration ◽  
Site Dependence ◽  
Oxygen Site ◽  
Insight Into

Oxygen migration on the surface of coronene (C24) epoxides and their persulfurated derivatives (PSCs) can be easily tuned by an external electric field and their low-lying states show a remarkable oxygen-site dependence.

scholarly journals Effect of DC Biased Voltage and Ion Temperature on Bounded Ion-Ion Plasma

2020 ◽  
Vol 25 (1) ◽  
pp. 61-67
Author(s):  
Anish Maskey ◽  
Atit Deuja ◽  
Suresh Basnet ◽  
Raju Khanal
Keyword(s):  
Electric Field ◽  
Strong Electric Field ◽  
Negative Ions ◽  
Simulation Method ◽  
Negative Ion ◽  
Ion Temperature ◽  
Plasma Parameters ◽  
Degree Of Ionization ◽  
Particle In Cell ◽  
Ion Plasma

 A one dimensional particle-in-cell (PIC) simulation method has been employed to study the effect of DC voltage and ion temperature on the properties of ion-ion plasma bounded by two symmetrical but oppositely biased electrodes. It is assumed that the ion-ion plasma is collisionless and both the positive and negative ion species have the same mass, temperature, and degree of ionization. Simulation results show that the formation of sheath and presheath regions and fluctuation of plasma parameters in that region are affected by the biasing voltage and ion temperature. It was found that the magnitude of the electrostatic electric field at the vicinity of biasing electrodes was affected by the biasing voltage and ion temperature as well. This strong electric field close to the electrodes further prevents the flow of charged particles towards the electrodes. The presence of a non-zero electric field at the quasineutral region suggests a presheath region similar to the electron-ion plasma. In the quasineutral region, the density of ions increased with the increase in biasing voltage and decreased with the increase in temperature of isothermal ions. Furthermore, the phase space diagrams for the ions were obtained which indicated different regions of the plasma. The positive ions acquire negative velocity towards the negatively biased electrode and the negative ions acquire positive velocity towards the positively biased electrode.

Electric Field Effect on NQR in Ferroelectric Materials

1996 ◽  
Vol 51 (5-6) ◽  
pp. 646-650 ◽  
Author(s):  
Jae Kap Jung ◽  
Hae Jin Kim ◽  
Kee Tae Han ◽  
Sung Ho Choh
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Field Effect ◽  
Ferroelectric Materials ◽  
Line Shift ◽  
Electric Field Effect ◽  
Ionic Crystals ◽  
Line Broadening ◽  
Nuclear Site ◽  
The Difference

Abstract The electric field effect on NQR in ferroelectric materials, 93Nb in LiNbO3 and 14N in NaNO2 and SC(NH2)2 , has been investigated at 77 K. In these crystals with single domain, only the line shift due to the external electric field was observed. In the case of NaNO2 powder and a crystal with multi-domains, line broadening was observed in the external electric field. These phenomena can be explained with the fact that the direction of spontaneous polarization in a domain is related to the direction of the applied electric field. The rate of the NQR line-shift due to the electric field is remarkably smaller in mostly ionic crystals, such as LiNbO3 and NaNO2 , than in a molecular crystal such as SC(NH2)2 . This is due to the strong ionic bonding in ionic crystals. Also, the difference of the Stark shift'between NaNO2 and SC(NH2)2 is discussed in terms of the local electric field and polarizability at the resonant nuclear site.

Photodetachment microscopy of H– ion in time-dependent electric and magnetic fields

2018 ◽  
Vol 96 (9) ◽  
pp. 961-968
Author(s):  
De-hua Wang
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Electric Field ◽  
Interference Pattern ◽  
Current Distribution ◽  
Time Dependent ◽  
Electron Current ◽  
Detector Plane ◽  
Electron Trajectories ◽  
Electric And Magnetic Fields

We examine the dynamics of electrons photodetached from the H– ion in time-dependent electric and magnetic fields for the first time. The photodetachment microscopy patterns caused by a time-dependent gradient electric field and magnetic field have been analyzed in great detail based on the semiclassical theory. The interplay of the gradient electric field and magnetic field forces causes an intricate shape of the electron wave and multiple electron trajectories generated by a fixed energy point source can arrive at a given point on the microchannel-plate detector. The interference effects between these electron trajectories cause the oscillatory structures of the electron probability density and electron current distribution, and a set of concentric interference fringes are found at the detector. Our calculation results suggest that the photodetachment microscopy interference pattern on the detector can be adjusted by the electron energy, magnetic field strength, and position of the detector plane. Under certain conditions, the interference pattern in the electron current distribution might be seen on the detector plane localized at a macroscopic distance from the photodetachment source, which can be observed in an actual photodetachment microscopy experiment. Therefore, we make predictions that our work should serve as a guide for future photodetachment microscopy experiments in time-dependent electric and magnetic fields.

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