scholarly journals Experimental Study of Quantum Structures in Solids

1991 ◽  
Vol 44 (3) ◽  
pp. 315
Author(s):  
Kaare J Nygaard
Keyword(s):  
Binding Energy ◽  
Molecular Spectroscopy ◽  
Carbon Film ◽  
Experimental System ◽  
Binding Energies ◽  
Beam Incident ◽  
Present Apparatus ◽  
Energy And Momentum ◽  
Position Sensitive Detectors ◽  
Atomic And Molecular Spectroscopy

The object of the experiment is to measure electron binding energy spectra in solids at a series of selected bound electron momenta. The present apparatus is based on developments in atomic and molecular spectroscopy and uses a 10 keY electron beam incident on a thin (80 A) amorphous carbon film. The exit electrons in the (e,2e) reaction are studied in a symmetric coplanar geometry using hemispherical analysers and position-sensitive detectors. The resultant coincidence count rate is proportional to the probability of finding a target electron with a given binding energy and momentum. Data were obtained with binding energies from 0 to 40 eV with momentum as parameter. Contributions from the rr and u bands are clearly demonstrated. Future investigations in a new experimental system will be devoted to single crystals of metals, semiconductors and macro-molecules.

A DFT study of spherands containing five anisyl groups — Highly preorganized to bind the alkali metal

2006 ◽  
Vol 84 (8) ◽  
pp. 1045-1049 ◽  
Author(s):  
Shabaan AK Elroby ◽  
Kyu Hwan Lee ◽  
Seung Joo Cho ◽  
Alan Hinchliffe
Keyword(s):  
Density Functional Theory ◽  
Binding Energy ◽  
Density Functional ◽  
Ionic Radius ◽  
Binding Energies ◽  
Cavity Size ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Good Agreement

Although anisyl units are basically poor ligands for metal ions, the rigid placements of their oxygens during synthesis rather than during complexation are undoubtedly responsible for the enhanced binding and selectivity of the spherand. We used standard B3LYP/6-31G** (5d) density functional theory (DFT) to investigate the complexation between spherands containing five anisyl groups, with CH2–O–CH2 (2) and CH2–S–CH2 (3) units in an 18-membered macrocyclic ring, and the cationic guests (Li+, Na+, and K+). Our geometric structure results for spherands 1, 2, and 3 are in good agreement with the previously reported X-ray diffraction data. The absolute values of the binding energy of all the spherands are inversely proportional to the ionic radius of the guests. The results, taken as a whole, show that replacement of one anisyl group by CH2–O–CH2 (2) and CH2–S–CH2 (3) makes the cavity bigger and less preorganized. In addition, both the binding and specificity decrease for small ions. The spherands 2 and 3 appear beautifully preorganized to bind all guests, so it is not surprising that their binding energies are close to the parent spherand 1. Interestingly, there is a clear linear relation between the radius of the cavity and the binding energy (R2 = 0.999).Key words: spherands, preorganization, density functional theory, binding energy, cavity size.

scholarly journals np-Pair Correlations in the Isovector Pairing Model

Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1405
Author(s):  
Feng Pan ◽  
Yingwen He ◽  
Lianrong Dai ◽  
Chong Qi ◽  
Jerry P. Draayer
Keyword(s):  
Binding Energy ◽  
Occupation Number ◽  
Mean Field ◽  
Energy Difference ◽  
Binding Energies ◽  
Pair Correlations ◽  
Isospin Symmetry Breaking ◽  
Pairing Model ◽  
Proton Pairing ◽  
Spin Basis

A diagonalization scheme for the shell model mean-field plus isovector pairing Hamiltonian in the O(5) tensor product basis of the quasi-spin SUΛ(2) ⊗ SUI(2) chain is proposed. The advantage of the diagonalization scheme lies in the fact that not only can the isospin-conserved, charge-independent isovector pairing interaction be analyzed, but also the isospin symmetry breaking cases. More importantly, the number operator of the np-pairs can be realized in this neutron and proton quasi-spin basis, with which the np-pair occupation number and its fluctuation at the J = 0+ ground state of the model can be evaluated. As examples of the application, binding energies and low-lying J = 0+ excited states of the even–even and odd–odd N∼Z ds-shell nuclei are fit in the model with the charge-independent approximation, from which the neutron–proton pairing contribution to the binding energy in the ds-shell nuclei is estimated. It is observed that the decrease in the double binding-energy difference for the odd–odd nuclei is mainly due to the symmetry energy and Wigner energy contribution to the binding energy that alter the pairing staggering patten. The np-pair amplitudes in the np-pair stripping or picking-up process of these N = Z nuclei are also calculated.

Interfacial Adhesion of Cu to Self-Assembled Monolayers on SiO2

2001 ◽  
Vol 695 ◽  
Author(s):  
G. Cui ◽  
M. Lane ◽  
K. Vijayamohanan ◽  
G. Ramanath
Keyword(s):  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Interfacial Adhesion ◽  
Adhesion Energy ◽  
Binding Energies ◽  
Self Assembled Monolayers ◽  
Chemical Binding ◽  
Barrier Materials ◽  
Assembled Monolayers ◽  
Self Assembled

ABSTRACTAs the critical feature size in microelectronic devices continues to decrease below 100 nm, new barrier materials of > 5 nm thickness are required. Recently we have shown that self-assembled monolayers (SAMs) are attractive candidates that inhibit Cu diffusion into SiO2. For SAMs to be used as barriers in real applications, however, they must also promote adhesion at the Cu/dielectric interfaces. Here, we report preliminary quantitative measurements of interfacial adhesion energy and chemical binding energy of Cu/SiO2 interfaces treated with nitrogen-terminated SAMs. Amine-containing SAMs show a ~10% higher adhesion energy with Cu, while interfaces with Cu-pyridine bonds actually show degraded adhesion, when compared with that of the reference Cu/SiN interface. However, X-ray photoelectron spectroscopy (XPS) measurements show that Cu-pyridine and Cu-amine interactions have a factor-of-four higher binding energy than that of Cu-N bonds at Cu/SiN interfaces. The lack of correlation between adhesion and chemical binding energies is most likely due to incomplete coverage of SAMs.

The binding energies of atomic nuclei III. Nuclear forces and the ground state of oxygen 16

1959 ◽  
Vol 253 (1273) ◽  
pp. 186-198 ◽  
Keyword(s):  
Binding Energy ◽  
Electron Scattering ◽  
Ground State ◽  
Binding Energies ◽  
Wave Functions ◽  
Unperturbed System ◽  
Core Radius ◽  
Nuclear Forces ◽  
Potential Core ◽  
Atomic Nuclei

The r. m. s. radius and the binding energy of oxygen 16 are calculated for several different internueleon potentials. These potentials all fit the low-energy data for two nucleons, they have hard cores of differing radii, and they include the Gammel-Thaler potential (core radius 0·4 fermi). The calculated r. m. s. radii range from 1·5 f for a potential with core radius 0·2 f to 2·0 f for a core radius 0·6 f. The value obtained from electron scattering experiments is 2·65 f. The calculated binding energies range from 256 MeV for a core radius 0·2 f to 118 MeV for core 0·5 f. The experimental value of binding energy is 127·3 MeV. The 25% discrepancy in the calculated r. m. s. radius may be due to the limitations of harmonic oscillator wave functions used in the unperturbed system.

scholarly journals Combinatorial Library Designing and Virtual Screening of Cryptolepine Derivatives against Topoisomerase II by Molecular Docking

2020 ◽  
Author(s):  
Maria ◽  
Zahid Khan
Keyword(s):  
Molecular Docking ◽  
Cell Division ◽  
Binding Energy ◽  
Cancer Cells ◽  
Anticancer Agents ◽  
Combinatorial Library ◽  
Topoisomerase Ii ◽  
Computational Study ◽  
Binding Energies ◽  
Potential Inhibitors

AbstractComputational approaches have emerging role for designing potential inhibitors against topoisomerase 2 for treatment of cancer. TOP2A plays a key role in DNA replication before cell division and thus facilitates the growth of cells. This function of TOP2A can be suppressed by targeting with potential inhibitors in cancer cells to stop the uncontrolled cell division. Among potential inhibitors cryptolepine is more selective and has the ability to intercalate into DNA, effectively block TOP2A and cease cell division in cancer cells. However, cryptolepine is non-specific and have low affinity, therefore, a combinatorial library was designed and virtually screened for identification of its derivatives with greater TOP2A binding affinities.A combinatorial library of 31114 derivatives of cryptolepine was formed and the library was virtually screened by molecular docking to predict the molecular interactions between cryptolepine derivatives and TOP2A taking cryptolepine as standard. The overall screening and docking approach explored all the binding poses of cryptolepine for TOP2A to calculate binding energy. The compounds are given database number 8618, 907, 147, 16755, and 8186 scored lowest binding energies of −9.88kcal/mol, −9.76kcal/mol, −9.75kcal/mol, −9.73kcal/mol, and −9.72kcal/mol respectively and highest binding affinity while cryptolepine binding energy is −6.09kcal/mol. The good binding interactions of the derivatives showed that they can be used as potent TOP2A inhibitors and act as more effective anticancer agents than cryptolepine itself. The interactions of derivatives with different amino acid residues were also observed. A comprehensive understanding of the interactions of proposed derivatives with TOP2A helped for searching more novel and potent drug-like molecules for anticancer therapy. This Computational study suggests useful references to understand inhibition mechanisms that will help in the modification of TOP2A inhibitors.

O 1s Core-Level Positions of Bi2Sr2CaCu2O8-x by OKα-Ray Emission

1989 ◽  
Vol 44 (9) ◽  
pp. 780-784
Author(s):  
F. Burgäzy ◽  
C. Politis ◽  
P. Lamparter ◽  
S. Steeb
Keyword(s):  
Binding Energy ◽  
Energy Level ◽  
Photoelectron Spectrum ◽  
Local Density ◽  
Binding Energies ◽  
Core Level ◽  
X Ray ◽  
Band Structure Calculations ◽  
Density Band ◽  
Structure Calculations

Abstract The measured O Kα X-ray emission spectrum of the high-Tc superconductor Bi2Sr2CaCu2O8-x is compared with a spectrum based on local density band structure calculations. By taking also into account the shape of the measured O 1s X-ray photoelectron spectrum an energy level diagram for the O 1s core-level binding energies of the three different oxygen sites is constructed. The O 1s binding energy in the Bi2O2-layers is found to be about the same as that one in the SrO-layers, whereas the binding energy in the CuO2-layers is lower by about 0.5 eV.

scholarly journals Positive and Negative Donor Impurity in an InAs/AlAs Quantum Wire

2010 ◽  
Vol 2 (3) ◽  
pp. 433
Author(s):  
N. Arunachalam ◽  
A. J. Peter
Keyword(s):  
Binding Energy ◽  
Quantum Wire ◽  
Optical Transition ◽  
Binding Energies ◽  
Impurity Level ◽  
Wire Radius ◽  
Emission Energy ◽  
Interband Optical Transition ◽  
Mass Approximation ◽  
Charged Donor

Binding energies of positive and negative charged donor impurities in an InAs/AlAs cylindrical quantum wire are investigated. Numerical calculations are performed using the variational procedure within the single band effective mass approximation. We assume that the impurity is located at the axis of the wire. The interband optical transition with and without the exciton is computed as a function of wire radius. The valence-band anisotropy is included in our theoretical model by using different hole masses in different spatial directions. Neutral shallow donors comprise a positively charged donor and a single bound electron. It is observed that (i) negative trions have a higher binding energy than positive trions, (ii) the binding energy of the heavy-hole exciton is much larger than that of the light-hole exciton due to different hole mass values (iii) the exciton binding energy and the interband emission energy are both increased when the radius of the cylindrical quantum wire is decreased and (iv) the effect of exciton influences the interband emission energy. Our results are in good agreement with the recent published results. Keywords: Quantum wire; Impurity level; Binding energy; Excitons. © 2010 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v2i3.4715                 J. Sci. Res. 2 (3), 433-441 (2010)  

scholarly journals Effect of RF Power on the Properties of Sputtered-CuS Thin Films for Photovoltaic Applications

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 688 ◽  
Author(s):  
Donghyeok Shin ◽  
SangWoon Lee ◽  
Dong Ryeol Kim ◽  
Joo Hyung Park ◽  
Yangdo Kim ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Binding Energy ◽  
Indium Tin Oxide ◽  
Short Circuit ◽  
Film Surface ◽  
Binding Energies ◽  
Tin Sulfide ◽  
Rf Power ◽  
Deposition Power

Copper sulfide (CuS) thin films were deposited on a glass substrate at room temperature using the radio-frequency (RF) magnetron-sputtering method at RF powers in the range of 40–100 W, and the structural and optical properties of the CuS thin film were investigated. The CuS thin films fabricated at varying deposition powers all exhibited hexagonal crystalline structures and preferred growth orientation of the (110) plane. Raman spectra revealed a primary sharp and intense peak at the 474 cm−1 frequency, and a relatively wide peak was found at 265 cm−1 frequency. In the CuS thin film deposited at an RF power of 40 W, relatively small dense particles with small void spacing formed a smooth thin-film surface. As the power increased, it was observed that grain size and grain-boundary spacing increased in order. The binding energy peaks of Cu 2p3/2 and Cu 2p1/2 were observed at 932.1 and 952.0 eV, respectively. Regardless of deposition power, the difference in the Cu2+ state binding energies for all the CuS thin films was equivalent at 19.9 eV. We observed the binding energy peaks of S 2p3/2 and S 2p1/2 corresponding to the S2− state at 162.2 and 163.2 eV, respectively. The transmittance and band-gap energy in the visible spectral range showed decreasing trends as deposition power increased. For the CuS/tin sulfide (SnS) absorber-layer-based solar cell (glass/Mo/absorber(CuS/SnS)/cadmium sulfide (CdS)/intrinsic zinc oxide (i-ZnO)/indium tin oxide (ITO)/aluminum (Al)) with a stacked structure of SnS thin films on top of the CuS layer deposited at 100 W RF power, an open-circuit voltage (Voc) of 115 mA, short circuit current density (Jsc) of 9.81 mA/cm2, fill factor (FF) of 35%, and highest power conversion efficiency (PCE) of 0.39% were recorded.

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