scholarly journals Role of the electric field in surface electron dynamics above the vacuum level

2007 ◽  
Vol 75 (16) ◽  
Author(s):  
J. I. Pascual ◽  
C. Corriol ◽  
G. Ceballos ◽  
I. Aldazabal ◽  
H.-P. Rust ◽  
...  
Keyword(s):  
Electric Field ◽  
Electron Dynamics ◽  
Surface Electron ◽  
Vacuum Level

scholarly journals Elucidating the Influence of Electric Fields toward CO2 Activation on YSZ (111)

Catalysts ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 271
Author(s):  
Nisa Ulumuddin ◽  
Fanglin Che ◽  
Jung-Il Yang ◽  
Su Ha ◽  
Jean-Sabin McEwen
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Heterogeneous Catalysts ◽  
Co2 Reduction ◽  
Total Density ◽  
Reverse Water Gas Shift ◽  
High Thermodynamic Stability ◽  
Shift Reaction ◽  
Water Gas

Despite its high thermodynamic stability, the presence of a negative electric field is known to facilitate the activation of CO2 through electrostatic effects. To utilize electric fields for a reverse water gas shift reaction, it is critical to elucidate the role of an electric field on a catalyst surface toward activating a CO2 molecule. We conduct a first-principles study to gain an atomic and electronic description of adsorbed CO2 on YSZ (111) surfaces when external electric fields of +1 V/Å, 0 V/Å, and −1 V/Å are applied. We find that the application of an external electric field generally destabilizes oxide bonds, where the direction of the field affects the location of the most favorable oxygen vacancy. The direction of the field also drastically impacts how CO2 adsorbs on the surface. CO2 is bound by physisorption when a +1 V/Å field is applied, a similar interaction as to how it is adsorbed in the absence of a field. This interaction changes to chemisorption when the surface is exposed to a −1 V/Å field value, resulting in the formation of a CO3− complex. The strong interaction is reflected through a direct charge transfer and an orbital splitting within the Olatticep-states. While CO2 remains physisorbed when a +1 V/Å field value is applied, our total density of states analysis indicates that a positive field pulls the charge away from the adsorbate, resulting in a shift of its bonding and antibonding peaks to higher energies, allowing a stronger interaction with YSZ (111). Ultimately, the effect of an electric field toward CO2 adsorption is not negligible, and there is potential in utilizing electric fields to favor the thermodynamics of CO2 reduction on heterogeneous catalysts.

scholarly journals The role of electric field, peripheral chains, and magnetic effects on significant 1H upfield shifts of the encapsulated molecules in chalcogen-bonded capsules

2021 ◽  
Vol 23 (35) ◽  
pp. 19647-19658
Author(s):  
Demeter Tzeli ◽  
Ioannis D. Petsalakis ◽  
Giannoula Theodorakopoulos ◽  
Faiz-Ur Rahman ◽  
Yang Yu ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Chemical Shifts ◽  
Electric Field Effects ◽  
Magnetic Effects ◽  
Field Effects ◽  
Equal Importance

Significant 1H upfield chemical shifts of the guests in the capsules are consequences of polarizability of chalcogens, electric field effects and peripheral chains. The effects of the electric field and of magnetic field are of equal importance.

scholarly journals Electric potential differences across auroral generator interfaces

2013 ◽  
Vol 31 (2) ◽  
pp. 251-261 ◽  
Author(s):  
J. De Keyser ◽  
M. Echim
Keyword(s):  
Electric Field ◽  
High Altitude ◽  
Electric Fields ◽  
Electric Potential ◽  
Equilibrium Configuration ◽  
Potential Difference ◽  
Field Profile ◽  
Electric Potential Difference ◽  
Electric Field Profile

Abstract. Strong localized high-altitude auroral electric fields, such as those observed by Cluster, are often associated with magnetospheric interfaces. The type of high-altitude electric field profile (monopolar, bipolar, or more complicated) depends on the properties of the plasmas on either side of the interface, as well as on the total electric potential difference across the structure. The present paper explores the role of this cross-field electric potential difference in the situation where the interface is a tangential discontinuity. A self-consistent Vlasov description is used to determine the equilibrium configuration for different values of the transverse potential difference. A major observation is that there exist limits to the potential difference, beyond which no equilibrium configuration of the interface can be sustained. It is further demonstrated how the plasma densities and temperatures affect the type of electric field profile in the transition, with monopolar electric fields appearing primarily when the temperature contrast is large. These findings strongly support the observed association of monopolar fields with the plasma sheet boundary. The role of shear flow tangent to the interface is also examined.

Role of internal electric field on suppression of superconductivity by Pr in copper oxides

1989 ◽  
Vol 161 (5-6) ◽  
pp. 574-580 ◽  
Author(s):  
X.X. Tang ◽  
A. Manthiram ◽  
J.B. Goodenough
Keyword(s):  
Electric Field ◽  
Copper Oxides ◽  
Internal Electric Field

Simulations of electric field at the initiation altitudes of sprites and halos generated by the thundercloud charge structure and lightning channels of causative return strokes

2021 ◽  
Author(s):  
Petr Kaspar ◽  
Ivana Kolmasova ◽  
Ondrej Santolik ◽  
Martin Popek ◽  
Pavel Spurny ◽  
...  
Keyword(s):  
Electromagnetic Field ◽  
Electric Field ◽  
Boundary Conditions ◽  
Free Space ◽  
Nonlinear Effects ◽  
Charge Structure ◽  
Transient Luminous Events ◽  
Lightning Channel ◽  
Free Parameters

<p><span>Sprites and halos are transient luminous events occurring above thunderclouds. They can be observed simultaneously or they can also appear individually. Circumstances leading to initiation of these events are still not completely understood. In order to clarify the role of lightning channels of causative lightning return strokes and the corresponding thundercloud charge structure, we have developed a new model of electric field amplitudes at halo/sprite altitudes. It consists of electrostatic and inductive components of the electromagnetic field generated by the lightning channel in free space at a height of 15 km. Above this altitude we solve Maxwell’s equations self-consistently including the nonlinear effects of heating and ionization/attachment of the electrons. At the same time, we investigate the role of a development of the thundercloud charge structure and related induced charges above the thundercloud. We show how these charges lead to the different distributions of the electric field at the initiation heights of the halos and sprites. We adjust free parameters of the model using observations of halos and sprites at the Nydek TLE observatory and using measurements of luminosity curves of the corresponding return strokes measured by an array of fast photometers. The latter measurements are also used to set the boundary conditions of the model.</span></p>

Picosecond Surface Electron Dynamics on Photoexcited Si(111) (2×1) Surfaces

1986 ◽  
Vol 57 (7) ◽  
pp. 881-884 ◽  
Author(s):  
J. Bokor ◽  
R. Storz ◽  
R. R. Freeman ◽  
P. H. Bucksbaum
Keyword(s):  
Electron Dynamics ◽  
Surface Electron
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