The Use of D Index in the Estimation of Aromaticity: The Case of Cycloparaphenylene

Cycloparaphenylenes are important compounds for their photophysical and electronic properties. The curved structure of these compounds induces an alteration of the aromatic character of these compounds. D values have been used to describe the aromatic character of compounds from [5]- to [10]cycloparaphenylene. D values are compared with HOMED and with the strain energy are obtained by using an homodesmotic reaction.

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Novel photoresponsive cyclicparaphenylenediazenes: structure, strain energy, cis–trans isomerization, and electronic properties

Photochemical & Photobiological Sciences ◽

10.1039/c8pp00502h ◽

2019 ◽

Vol 18 (5) ◽

pp. 1185-1196

Author(s):

Mohamad Akbar Ali ◽

Mohammad Abrar Alam

Keyword(s):

Electronic Properties ◽

Strain Energy ◽

Trans Isomerization ◽

Novel Structures

Novel structures and related properties of cyclicparaphenylenediazenes.

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Manganese Dioxides: Chemical-Structural Disorder, Electronic Properties, Electrochemical Activity and Proton Diffusivity

MRS Proceedings ◽

10.1557/proc-548-261 ◽

1998 ◽

Vol 548 ◽

Cited By ~ 1

Author(s):

C.J. Poinsignon

Keyword(s):

Diffusion Coefficient ◽

Chemical Composition ◽

Electronic Properties ◽

Reduction Rate ◽

Structural Disorder ◽

Electrochemical Activity ◽

Electrochemical Reactivity ◽

Electron Reduction ◽

D Values

ABSTRACTSeveral synthetic and natural manganese dioxides (MD) are characterized in terms of chemical composition, structural disorder and electrochemical activity; semi conducting properties are examined on pressed powdered samples. The reactivity scale established between structural disorder and electrochemical reactivity is paralleled by semi conducting properties and proton diffusivity. Conductivity values of 0.15 S.cm−1for stoechiometric β-MnO2, 1.3 10−2, 2.5 10−2 and 3.7 10−2 S.cm−1 for the defect dioxides, respectively Synthetic-Ramsdellite, CMD and EMD are measured. Proton diffusivity study by EIS provides, for low reduction rate, diffusion coefficient D values varying from 10–15 cm2/s value to 10−16 for the best reactive forms EMD and CMD; for NMD and β-MD, D is respectively 10−16 and 10−21 cm2/s. Redox reversibility is obtained around 1.3V (vs Hg.HgO) for EMD for a one electron reduction in [KOH] <IM; at -0.4V for a 2 electrons reduction in 9M KOH for Bi modified NMD.

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The wustite-spinel interface

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126226 ◽

1987 ◽

Vol 45 ◽

pp. 268-269

Author(s):

S.R. Summerfelt ◽

C.B. Carter

Keyword(s):

Solid State ◽

Solid State Reaction ◽

Strain Energy ◽

Matrix Material ◽

Lattice Misfit ◽

Solid State Reactions ◽

Oxygen Sublattice ◽

Large Particles ◽

Small Lattice ◽

Coherent Interfaces

The wustite-spinel interface can be viewed as a model interface because the wustite and spinel can share a common f.c.c. oxygen sublattice such that only the cations distribution changes on crossing the interface. In this study, the interface has been formed by a solid state reaction involving either external or internal oxidation. In systems with very small lattice misfit, very large particles (>lμm) with coherent interfaces have been observed. Previously, the wustite-spinel interface had been observed to facet on {111} planes for MgFe2C4 and along {100} planes for MgAl2C4 and MgCr2O4, the spinel then grows preferentially in the <001> direction. Reasons for these experimental observations have been discussed by Henriksen and Kingery by considering the strain energy. The point-defect chemistry of such solid state reactions has been examined by Schmalzried. Although MgO has been the principal matrix material examined, others such as NiO have also been studied.

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

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100176149 ◽

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.

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