Electron mobility in nonpolar liquids: the effect of molecular structure, temperature, and electric field

1977 ◽  
Vol 55 (11) ◽  
pp. 2197-2210 ◽  
Author(s):  
Werner F. Schmidt
Keyword(s):  
Molecular Structure ◽  
Electric Field ◽  
High Mobility ◽  
Liquid Hydrocarbons ◽  
Limited Temperature ◽  
Excess Electrons ◽  
Liquid Methane ◽  
Nonpolar Liquids ◽  
Electron Models ◽  
Related Compounds

A survey is given on the mobility of excess electrons in liquid hydrocarbons and related compounds. It was found that the mobility is strongly influenced by the molecular structure of the liquid, by the temperature, and by the electric field strength. The mobility in hydrocarbons increases as the shape of the molecule approaches a sphere. The temperature coefficient is positive in most liquids over a limited temperature although exceptions have been observed in liquid methane. The field dependence of the mobility in high mobility liquids (>10 cm2V−1s−1) showed a decrease of the mobility at higher field strengths while in low mobility liquids (<1 cm2V−1s−1) it showed an increase. These results are discussed on the basis of the extended and the localized electron models. The predictions of these theories are compared with the experimental results and conclusions on the validity of the underlying assumptions are drawn.

Excess Electrons and Positive Charge Carriers in Liquid Methane. I

1973 ◽  
Vol 28 (3-4) ◽  
pp. 511-518 ◽  
Author(s):  
George Bakale ◽  
Werner F. Schmidt
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Drift Velocity ◽  
Positive Charge ◽  
Charge Carriers ◽  
Excess Electrons ◽  
Radiation Induced ◽  
Liquid Methane ◽  
Increasing Temperature ◽  
Field Strengths

AbstractThe drift velocities of radiation-induced excess electrons and positive charge carriers in liquid methane were measured at different electric field strengths and several temperatures. For the excess electrons the drift velocity increases up to 1.5 kV cm-1 proportional to the electric field strength and a mobility of (400±50) cm2 V-1 s-1 at T = 111 °K was obtained. Above 1.5 kV cm-1 the drift velocity varies with E½. The temperature coefficient of the mobility is negative. For the positive charge carriers the measurements were carried out up to electric field strengths of 50 kV cm-1 and the drift velocity remained proportional to the field giving a mobility of (2.5 ± 0.5) · 10-3 cm2 V-1 s-1 at 7 = 111 °K. The mobility increased with increasing temperature. The reaction of excess electrons with oxygen was also studied and a rate constant of 8.4 · 1011 l mole-1 s-1 was obtained.

Field-dependent electron mobility in methane–ethane liquid mixtures

1977 ◽  
Vol 55 (11) ◽  
pp. 1952-1960 ◽  
Author(s):  
Bappanadu N. Rao ◽  
Robert L. Bush ◽  
K. Funabashi
Keyword(s):  
Experimental Data ◽  
High Field ◽  
High Mobility ◽  
Liquid Mixtures ◽  
Liquid Hydrocarbons ◽  
Field Dependent ◽  
Field Mobility ◽  
Excess Electrons ◽  
Effects Of Temperature ◽  
Hopping Model

Some aspects of the mobility of excess electrons in liquid hydrocarbons are discussed. Certain salient features of the experimental data on high-field mobility in ethane–methane mixtures are explained in terms of a hopping model, in which disorder plays an important role. The disorder is compositional, like that in a binary alloy, and enters the model in the form of two distinct jump distances for hopping motion. It is shown that decreasing the coherence length for a quasi-free electron increases the binding energy of a localized electron and hence affects the activation energy and rate of hopping. The effects of temperature and impurity concentration for high-mobility liquids are shown to be consistent with a scattering model.

scholarly journals Layer- and gate-tunable spin-orbit coupling in a high-mobility few-layer semiconductor

2021 ◽  
Vol 7 (5) ◽  
pp. eabe2892
Author(s):  
Dmitry Shcherbakov ◽  
Petr Stepanov ◽  
Shahriar Memaran ◽  
Yaxian Wang ◽  
Yan Xin ◽  
...  
Keyword(s):  
Electric Field ◽  
High Mobility ◽  
Orbit Coupling ◽  
Spin Splitting ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Quantum Oscillations ◽  
Out Of Plane ◽  
Order Of Magnitude ◽  
Spin Degeneracy

Spin-orbit coupling (SOC) is a relativistic effect, where an electron moving in an electric field experiences an effective magnetic field in its rest frame. In crystals without inversion symmetry, it lifts the spin degeneracy and leads to many magnetic, spintronic, and topological phenomena and applications. In bulk materials, SOC strength is a constant. Here, we demonstrate SOC and intrinsic spin splitting in atomically thin InSe, which can be modified over a broad range. From quantum oscillations, we establish that the SOC parameter α is thickness dependent; it can be continuously modulated by an out-of-plane electric field, achieving intrinsic spin splitting tunable between 0 and 20 meV. Unexpectedly, α could be enhanced by an order of magnitude in some devices, suggesting that SOC can be further manipulated. Our work highlights the extraordinary tunability of SOC in 2D materials, which can be harnessed for in operando spintronic and topological devices and applications.

Crystal and molecular structure of B,B-bis(p-tolyl)boroxazolidine and the orthorhombic form of B,B-diphenylboroxazolidine

1976 ◽  
Vol 54 (20) ◽  
pp. 3130-3141 ◽  
Author(s):  
Steven J. Rettig ◽  
James Trotter
Keyword(s):  
Molecular Structure ◽  
Statistical Analysis ◽  
Hydrogen Bonds ◽  
Crystal And Molecular Structure ◽  
Direct Methods ◽  
Length Variation ◽  
Full Matrix ◽  
Space Group ◽  
Phenyl Rings ◽  
Related Compounds

Crystals of B,B-bis(p-tolyl)boroxazolidine, 1c, are trigonal, a = 25.1028(9), c = 12.4184(7) Å, Z = 18, space group [Formula: see text]. And crystals of B,B-diphenylboroxazolidine, 1a, are orthorhombic, a = 17.6420(4), b = 14.2527(3), c = 10.205(1) Å, Z = 8, space group Pbca. Both structures were solved by direct methods and were refined by full-matrix least-squares procedures to final R values of 0.057 and 0.040 for 2230 and 1828 reflections with I ≥ 3σ(I) respectively. Both molecules have structures similar to related compounds and feature intermolecular N—H … O hydrogen bonds (N … O = 2.982(2) for 1c and 2.896(2) Å for 1a). Bond lengths are: for 1c; O—C, 1.413(3), O—B, 1.478(3), N—C, 1.488(3), N—B, 1.657(3), C(sp3)—C(sp3), 1.501(4), B—C, 1.616(3) and 1.623(3), mean C—C(ar), 1.395, N—H, 0.93(2) and 0.94(2), mean C(sp3)—H, 1.00, and mean C(ar)—H, 1.00 Å; for 1a; O—C, 1.409(2), O—B, 1.476(2), N—C, 1.489(2), N—B, 1.655(2), C(sp3)—C(sp3), 1.507(3), B—C, 1.613(2) and 1.620(2), mean C—C(ar), 1.391, N—H, 0.93(2) and 0.92(2), mean C(sp3)—H, 1.00, and mean C(ar)—H, 0.98 Å. A statistical analysis of the phenyl C—C distances in compounds 1a, 1b, and 1c has provided an example of statistically significant substituent-induced bond length variation in the phenyl rings.

scholarly journals Modeling the Antileukemia Activity of Ellipticine-Related Compounds: QSAR and Molecular Docking Study

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 24 ◽  
Author(s):  
Edgar Márquez ◽  
José R. Mora ◽  
Virginia Flores-Morales ◽  
Daniel Insuasty ◽  
Luis Calle
Keyword(s):  
Molecular Structure ◽  
Binding Free Energy ◽  
Docking Study ◽  
Quantitative Structure Activity Relationship ◽  
Quantitative Structure ◽  
Molecular Docking Study ◽  
Modeling Simulation ◽  
Structure Activity ◽  
Related Compounds ◽  
Cancer Activity

The antileukemia cancer activity of organic compounds analogous to ellipticine representes a critical endpoint in the understanding of this dramatic disease. A molecular modeling simulation on a dataset of 23 compounds, all of which comply with Lipinski’s rules and have a structure analogous to ellipticine, was performed using the quantitative structure activity relationship (QSAR) technique, followed by a detailed docking study on three different proteins significantly involved in this disease (PDB IDs: SYK, PI3K and BTK). As a result, a model with only four descriptors (HOMO, softness, AC1RABAMBID, and TS1KFABMID) was found to be robust enough for prediction of the antileukemia activity of the compounds studied in this work, with an R2 of 0.899 and Q2 of 0.730. A favorable interaction between the compounds and their target proteins was found in all cases; in particular, compounds 9 and 22 showed high activity and binding free energy values of around −10 kcal/mol. Theses compounds were evaluated in detail based on their molecular structure, and some modifications are suggested herein to enhance their biological activity. In particular, compounds 22_1, 22_2, 9_1, and 9_2 are indicated as possible new, potent ellipticine derivatives to be synthesized and biologically tested.

Yields of Free Ions in the X Radiolysis of Some Simple Saturated and Unsaturated Hydrocarbon Liquids: Effects of Molecular Structure and Temperature

1971 ◽  
Vol 49 (22) ◽  
pp. 3657-3664 ◽  
Author(s):  
M. G. Robinson ◽  
P. G. Fuochi ◽  
G. R. Freeman
Keyword(s):  
Molecular Structure ◽  
Interaction Model ◽  
Unsaturated Hydrocarbon ◽  
The Other ◽  
Coulombic Interaction ◽  
Secondary Electrons ◽  
Free Ions ◽  
Free Ion ◽  
Liquid Methane ◽  
Hydrocarbon Molecules

Pulse techniques were used at temperatures ranging from 120 to 293 °K. A quasifree electron conductance transient (k/u overshoot) was observed in liquid methane, but not in ethane, propane, cyclopropane, ethylene, propylene or butene-1. The free ion yield in methane, Gfi = 0.8 at 120 °K, is much larger than those in the other liquids, which at 183°K are: ethane, 0.13; propane, 0.076; cyclopropane, 0.04; ethylene, 0.017; propylene, 0.04; butene-1, 0.027. The activation energies of free ion formation are, in kcal/mol: ethane, 0.6; propane, 0.8; ethylene, 0.5; propylene, 1.0; butene-1, 1.0. The results are interpreted in terms of the coulombic interaction model. The distances that the secondary electrons penetrate the liquid away from their parent ions are greater when the hydrocarbon molecules are more sphere-like, and are reduced by the presence of a π bond in the molecule. Cyclopropane behaves somewhat like an olefin in this regard, a fact that is explained by the unusual bonding in the C3 ring. In the present liquids the only ionization events that contribute appreciably to the free ion yield are those in which the electron penetrates [Formula: see text] from the parent ion.

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