Synthesis, structure and electronic properties of octakis(.mu.3-sulfido)hexakis(triethylphosphine)hexatungsten as a tungsten analog of the molecular model for superconducting Chevrel phases

1989 ◽  
Vol 28 (18) ◽  
pp. 3588-3592 ◽  
Author(s):  
Taro Saito ◽  
Akihiko Yoshikawa ◽  
Tsuneaki Yamagata ◽  
Hideo Imoto ◽  
Kei Unoura
Keyword(s):  
Electronic Properties ◽  
Molecular Model ◽  
Chevrel Phases

Rutile Molecular Model and its EUC Determination by PM7

2014 ◽  
Vol 976 ◽  
pp. 260-264
Author(s):  
C.H. Rios-Reyes ◽  
Luis Humberto Mendoza Huizar ◽  
Juan Coreño-Alonso
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Chemical Potential ◽  
Molecular Model ◽  
Theoretical Calculations ◽  
Chemical Reactivity ◽  
Total Hardness ◽  
Physical Parameters ◽  
Reactivity Descriptors ◽  
Cluster Properties

Rutile surface has been modeled in order to study its electronic properties as well as to determine its surface chemical reactivity. There have been constructed 10 different rutile structures, from a 6 atoms cluster (for the smallest) to a 356 atoms cluster (for the biggest). It was calculated for each cluster some physical parameters which are related to the electronic properties, such as work function, band gap, and density of states (DOS), in order to analyze the tendency of the cluster properties with the increase of atoms. From the data obtained, it was determined the Electronic Unit Cell (EUC), which refers to the modeled structure for what the electronic and reactivity properties of the system does no change, from clusters with different number of atoms. From the rutile EUC cluster it was determined its band gap with a value of 3.28 eV, which agreed with the experimental value of 3.0-3.1 eV. Furthermore, it was performed a reactivity surface study, which comprised the analysis of reactivity descriptors such as ionization potential, electronic affinity, total hardness, electronic chemical potential, electrophilicity and electronegativity. All theoretical calculations were performed using the semiempirical PM7 included in the 2012 version of MOPAC and the surfaces were modeled from crystallographic data.

Electronic properties of Chevrel phases by positron angular correlation

1981 ◽  
Vol 81 (1) ◽  
pp. 71-74 ◽  
Author(s):  
S. Ramasamy ◽  
T. Nagarajan ◽  
A.M. Umarji ◽  
G.V.Subba Rao
Keyword(s):  
Electronic Properties ◽  
Angular Correlation ◽  
Chevrel Phases

Toward an alignment of the actin molecule within the actin filament

1983 ◽  
Vol 41 ◽  
pp. 450-451
Author(s):  
P.R. Smith ◽  
W.E. Fowler ◽  
U. Aebi
Keyword(s):  
Actin Filament ◽  
Diffraction Data ◽  
Quantitative Estimate ◽  
Molecular Model ◽  
Quantitative Comparison ◽  
Regulatory Proteins ◽  
Essential Information ◽  
X Ray ◽  
Maximum Resolution ◽  
Lack Of Information

An understanding of the specific interactions of actin with regulatory proteins has been limited by the lack of information about the structure of the actin filament. Molecular actin has been studied in actin-DNase I complexes by single crystal X-ray analysis, to a resolution of about 0.6nm, and in the electron microscope where two dimensional actin sheets have been reconstructed to a maximum resolution of 1.5nm. While these studies have shown something of the structure of individual actin molecules, essential information about the orientation of actin in the filament is still unavailable.The work of Egelman & DeRosier has, however, suggested a method which could be used to provide an initial quantitative estimate of the orientation of actin within the filament. This method involves the quantitative comparison of computed diffraction data from single actin filaments with diffraction data derived from synthetic filaments constructed using the molecular model of actin as a building block. Their preliminary work was conducted using a model consisting of two juxtaposed spheres of equal size.

Exploration of cell wall architecture with the rapid-freeze deep-etch technique

1993 ◽  
Vol 51 ◽  
pp. 128-129
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Chris Hawes
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cell Biology ◽  
Molecular Model ◽  
Three Dimensional ◽  
Secretory Activity ◽  
Wall Structure ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

Structural properties of GaAs/InGaAs/GaAs (001) and InGaAs/GaAs (001) heterostructures and correlation with electronic properties

1990 ◽  
Vol 48 (4) ◽  
pp. 602-603
Author(s):  
J.M. Bonar ◽  
R. Hull ◽  
R. Malik ◽  
R. Ryan ◽  
J.F. Walker
Keyword(s):  
Band Gap ◽  
Electronic Properties ◽  
Gaas Substrate ◽  
Critical Thickness ◽  
Lattice Mismatch ◽  
Band Offset ◽  
Misfit Dislocations ◽  
Gaas Substrates ◽  
Gaas Structure ◽  
Low X

In this study we have examined a series of strained heteropeitaxial GaAs/InGaAs/GaAs and InGaAs/GaAs structures, both on (001) GaAs substrates. These heterostructures are potentially very interesting from a device standpoint because of improved band gap properties (InAs has a much smaller band gap than GaAs so there is a large band offset at the InGaAs/GaAs interface), and because of the much higher mobility of InAs. However, there is a 7.2% lattice mismatch between InAs and GaAs, so an InxGa1-xAs layer in a GaAs structure with even relatively low x will have a large amount of strain, and misfit dislocations are expected to form above some critical thickness. We attempt here to correlate the effect of misfit dislocations on the electronic properties of this material.The samples we examined consisted of 200Å InxGa1-xAs layered in a hetero-junction bipolar transistor (HBT) structure (InxGa1-xAs on top of a (001) GaAs buffer, followed by more GaAs, then a layer of AlGaAs and a GaAs cap), and a series consisting of a 200Å layer of InxGa1-xAs on a (001) GaAs substrate.

Sign in / Sign up

Export Citation Format

Share Document