Intrinsic charge transfer in the mixed halide PtCl«I−« linear chain solids

Single wall carbon nanotubes (SWNT) were doped with iodine, resulting in charge transfer between the iodine and carbon [1]. It was found that the iodine intercalation is air stable and also reversible by simple heat treatment. This behavior is in contrast to graphite and fullerenes which do not form charge transfer compounds with iodine. Although the iodine-induced charge transfer was not found in any other carbon polymorph solid, it has been found in some low dimensional organic polymers such as polyaniline,[2] forming charged linear-chain polyiodides (I3)- and (I5)-. This suggests that the geometric configuration of the carbon may play a very important role in iodine intercalation. In this study, we use Z-contrast imaging[3] in a VG Microscopes HB603U STEM to directly observe the configuration of iodine within the nanotube bundles. First-principles density-functional calculations are then used to explain the preference for the observed iodine configuration within the nanotubes.

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Low-Energy Charge Excitations in an Undoped Cuprate: Description Beyond the Standard pdσ-Model?

International Journal of Modern Physics B ◽

10.1142/s0217979203021745 ◽

2003 ◽

Vol 17 (18n20) ◽

pp. 3324-3328 ◽

Cited By ~ 1

Author(s):

S.-L. Drechsler ◽

J. Málek ◽

R. Hayn ◽

M. Knupfer ◽

A. S. Moskvin ◽

...

Keyword(s):

Charge Transfer ◽

Continued Fraction ◽

Theoretical Study ◽

Linear Chain ◽

Energy Charge ◽

Low Energy ◽

Final States ◽

Density Response ◽

Electron Energy Loss

Within a joint experimental and theoretical study the density-density response of the prototypical linear chain compound Sr 2 CuO 3 has been investigated by means of polarization and momentum dependent electron energy loss spectroscopy (EELS) and exact diagonalizations including also the continued fraction technique for the determination of spectral densities such as the optical conductivity and the loss function, respectively. It has been shown that the lowest charge excitations of this 1D charge transfer insulator cannot be described properly within the usual pdσ-model for cuprates which is based on the Cu 3dx2-y2 and the corresponding O 2pσ states, only. The lowest energy charge excitations are dominated by O 2pπ final states within the CuO 4 plaquette plane. A detailed analysis of the EELS-data allows a classification into two types of charge transfer excitations with predominant π and σ character and various sizes of internal localization and dispersion.

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Base-Pairs’ Correlated Oscillation Effects on the Charge Transfer in Double-Helix B-DNA Molecules

Materials ◽

10.3390/ma13225119 ◽

2020 ◽

Vol 13 (22) ◽

pp. 5119

Author(s):

Enrique Maciá

Keyword(s):

Charge Transfer ◽

Double Helix ◽

Linear Chain ◽

Low Frequency ◽

Dynamical Equations ◽

Base Pairs ◽

Double Stranded Dna ◽

Transfer Integrals ◽

Electronic Parameters ◽

Collective Oscillations

By introducing a suitable renormalization process, the charge carrier and phonon dynamics of a double-stranded helical DNA molecule are expressed in terms of an effective Hamiltonian describing a linear chain, where the renormalized transfer integrals explicitly depend on the relative orientations of the Watson–Crick base pairs, and the renormalized on-site energies are related to the electronic parameters of consecutive base pairs along the helix axis, as well as to the low-frequency phonons’ dispersion relation. The existence of synchronized collective oscillations enhancing the π-π orbital overlapping among different base pairs is disclosed from the study of the obtained analytical dynamical equations. The role of these phonon-correlated, long-range oscillation effects on the charge transfer properties of double-stranded DNA homopolymers is discussed in terms of the resulting band structure.

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Study of charge transfer in FeTi

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075270 ◽

1983 ◽

Vol 41 ◽

pp. 296-297

Author(s):

J. Taft∅

Keyword(s):

Charge Transfer ◽

Charge Distribution ◽

Electron Scattering ◽

Periodic System ◽

Electron Distribution ◽

Scattering Amplitude ◽

Transition Elements ◽

Hartree Fock ◽

Cscl Structure ◽

The Right

It is well known that for reflections corresponding to large interplanar spacings (i.e., sin θ/λ small), the electron scattering amplitude, f, is sensitive to the ionicity and to the charge distribution around the atoms. We have used this in order to obtain information about the charge distribution in FeTi, which is a candidate for storage of hydrogen. Our goal is to study the changes in electron distribution in the presence of hydrogen, and also the ionicity of hydrogen in metals, but so far our study has been limited to pure FeTi. FeTi has the CsCl structure and thus Fe and Ti scatter with a phase difference of π into the 100-ref lections. Because Fe (Z = 26) is higher in the periodic system than Ti (Z = 22), an immediate “guess” would be that Fe has a larger scattering amplitude than Ti. However, relativistic Hartree-Fock calculations show that the opposite is the case for the 100-reflection. An explanation for this may be sought in the stronger localization of the d-electrons of the first row transition elements when moving to the right in the periodic table. The tabulated difference between fTi (100) and ffe (100) is small, however, and based on the values of the scattering amplitude for isolated atoms, the kinematical intensity of the 100-reflection is only 5.10-4 of the intensity of the 200-reflection.

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Fractionation of polymethylene chains: An electron crystallographic investigation

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145315 ◽

1986 ◽

Vol 44 ◽

pp. 794-795

Author(s):

Douglas L. Dorset

Keyword(s):

Cross Section ◽

Binary Systems ◽

Linear Chain ◽

Pure Component ◽

Organic Substrates ◽

Crystallographic Investigation ◽

X Ray Diffraction ◽

X Ray ◽

Molecular Sizes ◽

The Stability

A variety of linear chain materials exist as polydisperse systems which are difficultly purified. The stability of continuous binary solid solutions assume that the Gibbs free energy of the solution is lower than that of either crystal component, a condition which includes such factors as relative molecular sizes and shapes and perhaps the symmetry of the pure component crystal structures.Although extensive studies of n-alkane miscibility have been carried out via powder X-ray diffraction of bulk samples we have begun to examine binary systems as single crystals, taking advantage of the well-known enhanced scattering cross section of matter for electrons and also the favorable projection of a paraffin crystal structure posited by epitaxial crystallization of such samples on organic substrates such as benzoic acid.

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