TITLE

Ionic conduction in one dimension: A structural study of the hollandite K1.54Mg0.77Ti7.23O16 over the range 133≤T≤919 K

AUTHOR(S)
Weber, Hans-Peter; Schulz, Heinz
PUB. DATE
July 1986
SOURCE
Journal of Chemical Physics;7/1/1986, Vol. 85 Issue 1, p475
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
Joint probability density functions (pdf) of the mobile K atom (and their corresponding pseudopotentials) have been obtained from seven x-ray (MoKα) intensity data sets collected on a one-dimensional conductor with the hollandite structure (K1.54Mg0.77Ti7.23O16; space group I4/m; Z=1). The data were collected at high resolution [(sin θ/λ)max ≥0.9 Å-1] and at several temperatures (133, 298, 387, 459, 540, 707, and 919 K) in order to determine the conduction mechanism. Two models of the K distribution within the strand of cavities making up the conduction tunnel have been refined. In the most complex model B [Rw(F) =0.02], up to four atomic positions are needed to describe the observed electron density. The pdfs show that—already at room temperature and within undamaged segments of the conduction tunnel—potassium ions diffuse at a high rate across the bottleneck between two neighboring cavities. Below about 430 K the potassium ions preferentially occupy sites shifted off the cavity center in the direction of the bottleneck; above this temperature the cavity center becomes the preferred location. At 298 K the potential barrier at the bottleneck amounts to 0.032(4) eV. In a plot of the cell constants vs T an inflection shows up at 387
ACCESSION #
7608130

 

Related Articles

  • Study Of Electron Density Of States Of Nano Structured Functionalized Graphene Within DFT Calculations. Sharma, Jyoti Dhar; Ahluwalia, P. K.; Kumar, Naveen // AIP Conference Proceedings;12/12/2011, Vol. 1393 Issue 1, p321 

    Calculations based on the method of numeric localized atomic orbitals, pseudopotentials and DFT are presented using SIESTA code for the study of Electronic Density of States(DOS) of nano structured functionalized graphene. This material has emerged as an amazing material for microelectronic...

  • Chemical bond in alkali metal sulfates. Zhuravlev, Yu.; Zhuravleva, L.; Golovko, O. // Journal of Structural Chemistry;Sep2007, Vol. 48 Issue 5, p789 

    In the context of the density functional theory of the local electron density the valence and differential density distribution in crystalline sulfates of M2SO4 (M is Li, Rb, and Cs) and double sulfates of MLiSO4 were calculated using the pseudopotential method in the basis set of numerical...

  • Effect of oxygen on structure and electronic properties of silicon nanoclusters Si n ( n = 5, 6, 10, 18). Gnidenko, A. A.; Zavodinsky, V. G. // Semiconductors;Jul2008, Vol. 42 Issue 7, p800 

    Methods of the theory of electron-density functional and pseudopotentials are used for studying the effect of oxygen on the geometry and electronic structure of small silicon clusters Si n , ( n = 5, 6, 10, 18). It is shown that the energy gap varies and, as a rule, decreases for such systems...

  • Orbital-Free Density Functional Theory for Molecular Structure Calculations. Huajie Chen; Aihui Zhou // Numerical Mathematics: Theory, Methods & Applications;Feb2008, Vol. 1 Issue 1, p1 

    We give here an overview of the orbital-free density functional theory that is used for modeling atoms and molecules. We review typical approximations to the kinetic energy, exchange-correlation corrections to the kinetic and Hartree energies, and constructions of the pseudopotentials. We...

  • Density-functional calculations of the structures, binding energies, and spin multiplicities of Fe–C clusters. Noya, E.G.; Longo, R.C.; Gallego, L.J. // Journal of Chemical Physics;12/1/2003, Vol. 119 Issue 21, p11130 

    We report ab initio calculations of the structures, binding energies and spin multiplicities of the clusters Fe[sub 2], C[sub 2], FeC[sub n] (n=1–4) and Fe[sub 2]C[sub n] (n=1–3) using a density-functional method that employs linear combinations of atomic orbitals as basis sets,...

  • A first-principles study of enhanced dielectric responses in Ti and Ce doped HfO2. Dutta, Gargi // Applied Physics Letters;1/5/2009, Vol. 94 Issue 1, p012907 

    In this letter, the dielectric response in Ti and Ce doped hafnia (HfO2) has been investigated by density functional theory calculations based on pseudopotentials, plane wave basis, and local density approximation. It is found that Ti doped samples give greater dielectric response than Ce doped...

  • Study on the maximum accuracy of the pseudopotential density functional method with localized atomic orbitals versus plane-wave basis sets. Gusso, Michele // Journal of Chemical Physics;1/28/2008, Vol. 128 Issue 4, p044102 

    A detailed study on the accuracy attainable with numerical atomic orbitals in the context of pseudopotential first-principles density functional theory is presented. Dimers of first- and second-row elements are analyzed: bond lengths, atomization energies, and Kohn-Sham eigenvalue spectra...

  • Fukui function from a gradient expansion formula, and estimate of hardness and covalent radius for an atom. Chattaraj, Pratim K.; Cedillo, Andrés; Parr, Robert G. // Journal of Chemical Physics;12/22/1995, Vol. 103 Issue 24, p10621 

    The Fukui function for a neutral atom is expressed as its LDA approximation plus a one-parameter gradient correction, and the resultant formula is numerically tested. Expressing hardness as a density functional involving this Fukui function, global hardness values are determined for several...

  • Ground state properties of cesium dimers from ab initio pseudopotential approaches. Moullet, I.; Andreoni, Wanda; Giannozzi, P. // Journal of Chemical Physics;6/15/1989, Vol. 90 Issue 12, p7306 

    We present the results of several calculations of the ground state of Cs2 and Cs+2 performed in the local-spin-density approximation of density functional theory, and using different approximations for the core electrons in the derivation of ab initio norm-conserving pseudopotentials. We...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics