Browsing Zwanziger, Josef W. by Title
Now showing items 117 of 17

Densityoperator theory of orbital magnetic susceptibility in periodic insulators
The theoretical treatment of homogeneous static magnetic fields in periodic systems is challenging, as the corresponding vector potential breaks the translational invariance of the Hamiltonian. Based on density operators ... 
Designing glass with nondispersive stressoptic response
The dispersion of the stressoptic response of a series of barium and lead phosphate glasses is measured using an ellipsometric method. It is found that the barium glasses display consistently positive dispersion with ... 
Firstprinciples study of the nuclear quadrupole resonance parameters and orbital ordering in LaTiO3.
The electronic structure of the distorted perovskite LaTiO3 is studied using d.functional theory, implemented with a projectoraugmented wave formalism together with the locald. approxn. plus Hubbard Uparameter (LDA+U) ... 

The heat capacities of thermomiotic ScF3 and ScF3–YF3 solid solutions
Scandium trifluoride (ScF3) exists in a cubic ReO3 structure that exhibits negative thermal expansion from 10 to 1100 K, while substituted Sc1−x Y x F3 materials display the same behavior at room temperature but transition ... 
Measuring the Geometric Component of the TransitionProbability in a 2Level System
We describe the measurement of a component of the nonadiabatic transition probability in a twolevel system that depends only on the path through parameter space followed by the Hamiltonian, and not on how fast the path ... 
Mechanical–Structural Investigation of IonExchanged Lithium Silicate Glass using MicroRaman Spectroscopy
MicroRaman spectroscopy was used to determine the structural modifications occurring in a simple ionexchanged glass. The base lithium silicate composition 30Li2O–70SiO2 was studied as it underwent ion exchange, Li+ ↔ K+, ... 
Nanoindentation Study of the Surface of IonExchanged Lithium Silicate Glass
Variations in mechanical properties (stiffness and hardness) were measured as a function of case depth in ionexchange glasses using nanoindentation. A simple silicate composition, 30Li2O–70Si2O, was exchanged (Li+ ↔ K+) ... 

Phonon dispersion and Gruneisen parameters of zinc dicyanide and cadmium dicyanide from first principles: Origin of negative thermal expansion.
Zinc dicyanide, Zn(CN)2, and the isostructural cadmium dicyanide show neg. thermal expansion over a broad range of temps. By the use of d. functional theory calcns., we det. the phonon dispersion curves of these materials ... 
Relating 139La Quadrupolar Coupling Constants to Polyhedral Distortion in Crystalline Structures
A broad series of crystalline lanthanum oxidebased materials has been investigated through highfield 139La solid state nuclear magnetic resonance (ssNMR) spectroscopy and ab initio density functional theory (DFT) ... 
Sodium distribution in sodium tellurite glasses probed with spinecho NMR
We present results on the spatial distribution of sodium cations in sodium tellurite glasses as a function of sodium oxide content, obtained using a spinecho NMR experiment. Glasses were studied with sodium oxide content ... 
Structure and Disorder of Phosphates in Ag2oAgiP2o5 Glasses
We directly probe the microstructure of the different phosphates in several glasses in the Ag2OAgIP2O5 system, by means of variable angle correlation NMR spectroscopy. This twodimensional experiment separates the ... 
Temperature dependent lattice misfit and coherency of Al3X (X = Sc, Zr, Ti and Nb) particles in an Al matrix
The lattice coherency and critical radii for Al3X precipitates in an aluminum matrix were computed using firstprinciples methods. From density functional perturbation theory and the quasiharmonic approximation, the unit ... 
Thermal, vibrational, and thermoelastic properties of Y2Mo3O12 and their relations to negative thermal expansion
Y2 Mo3O12, a material that exhibits negative thermal expansion (NTE) from 10 to 1173 K, offers an excellent opportunity to examine relationships between NTE and other physical properties over a wide temperature range. We ... 
Topological constraints and the Makishima–Mackenzie model
Computations of the elastic properties of networks with bond stretch and bond angle bend forces are carried out in order to study their behavior as a function of average coordination number. It is found that the elastic ... 
Zero Thermal Expansion in ZrMgMo3O12: NMR Crystallography Reveals Origins of Thermoelastic Properties
The coefficient of thermal expansion of ZrMgMo3O12 has been measured and was found to be extremely close to zero over a wide temperature range including room temperature ( = (1.6 ± 0.2) × 10–7 K–1 from 25 to 450 °C by Xray ...