A method for increasing the rate of convergence of general crystal lattice sums of the type \sum_{j \ne k} qjqkr−njk is described. The method is applicable for n > 3, or for n > 0 if \sum_{\rm cell} qj = 0. A numerical example is given for the London dispersion energy (n = 6) of the benzene crystal. The calculation ef…

Chemical Thermodynamics and Molecular StructureThermodynamic and Structural Properties of Metals and AlloysX-ray Diffraction in Crystallography

Three-dimensional Reconstruction from Radiographs and Electron Micrographs: Application of Convolutions instead of Fourier Transforms

G. N. Ramachandran、A. V. Lakshminarayanan1971-09-01OpenAlex

A new technique is proposed for the mathematical process of reconstruction of a three-dimensional object from its transmission shadowgraphs; it uses convolutions with functions defined in the real space of the object, without using Fourier transforms. The object is rotated about an axis at right angles to the directio…

Advanced X-ray Imaging TechniquesAdvanced Electron Microscopy Techniques and ApplicationsElectron and X-Ray Spectroscopy Techniques

Simple Molecular Model for the SmecticAPhase of Liquid Crystals

W. L. McMillan1971-09-01OpenAlex

The Maier-Saupe model of the nematic phase with an orientational order parameter is extended to the smectic $A$ phase by introducing a new order parameter, the amplitude of a density wave in the direction of the nematic preferred axis. Self-consistent equations for the two order parameters are derived from an anisotro…

Molecular spectroscopy and chiralityLiquid Crystal Research AdvancementsNonlinear Dynamics and Pattern Formation

The Photoelectric Effect at the Metal–Electrolyte Boundary

L. I. Korshunov、Ya. M. Zolotovitskii、V. A. Benderskiǐ1971-08-31Russian Chemical Reviews

Photoelectrochemistry is a new branch of physical chemistry, with many applications in the study of boundary layer structure, the energetics of electrons in solutions, the mechanism of photoemission, and the kinetics of fast reactions in solutions initiated by solvated electrons. 110 references.

Electron and X-Ray Spectroscopy TechniquesIron oxide chemistry and applicationsCorrosion Behavior and Inhibition

Thermoluminescence of X-ray irradiated KBr and KBr:Cu crystals

Y. V. G. S. Murti、K R N Murthy、C. Ramasastry1971-08-31Journal of Physics C Solid State Physics

The thermoluminescence of X-ray irradiated KBr and KBr:Cu crystals has been studied in the temperature range 300-510 K. Four glow peaks with first order kinetics are observed at 359, 377, 392 and 409 K for a warming rate 40 K min -1 . The trap depths for the above peaks are respectively 0.86, 0.97, 1.00 and 1.05 eV. T…

Nuclear materials and radiation effectsRadiation Detection and Scintillator TechnologiesLuminescence Properties of Advanced Materials

Dislocation mobility in zinc at low temperatures

Ya. M. Soǐfer、V.G. Shteinberg1971-08-16physica status solidi (a)

The dislocation mobility in zinc single crystals was investigated by measuring the shear modulus changes at frequencies of ≈ 10 Hz over the temperature range from 100 to 300 °K. The activation parameters of dislocation motion in basal (0001) 〈11―20〉 and pyramidal {11―22} 〈1123〉 slip systems were determined. From the r…

Material Properties and Failure MechanismsElectromagnetic Effects on MaterialsMicrostructure and mechanical properties

The temperature hysteresis of the current–voltage characteristics of thin semiconducting films

J. Krempaský、J. Červenãk、Peter Dieška 等 4 位作者1971-08-16physica status solidi (a)

The problem of the current–voltage characteristics of thin semiconducting films has been investigated. The sandwich configuration of films with metal electrodes was used and measurements were performed by increasing and decreasing the current and voltage, respectively. It is shown that there is a hysteresis of the cur…

Semiconductor Quantum Structures and DevicesPhase-change materials and chalcogenidesSemiconductor materials and interfaces

The electronic levels of the F t centre in MgO and CaO

M J Norgett1971-08-16Journal of Physics C Solid State Physics

The author has used Gaussian wavefunctions in a study of the F t centre in MgO and CaO. It is shown that Gaussian wavefunctions are very suitable for defect centre calculations because the integrals over the Madelung potential may be obtained analytically using Ewald's method of lattice summation. The calculation of B…

Surface and Thin Film PhenomenaMetallurgical and Alloy ProcessesNon-Destructive Testing Techniques

Submicroscopic-Void Resonance: The Effect of Internal Roughness on Optical Absorption

F. L. Galeener1971-08-16Physical Review Letters

An expression is developed for the optical dielectric constant of a medium containing submicroscopic voids. For an absorbing host medium, voids introduce additional optical structure resembling that due to surface roughness. Void resonance absorption may account for unexplained structure recently reported in the optic…

Surface Roughness and Optical MeasurementsPhotonic Crystals and ApplicationsGlass properties and applications

Optical Activity of Ferroelectric 5PbO·3GeO2 Single Crystals

Hiroshi Iwasaki、Kiyomasa Sugii1971-08-15Applied Physics Letters

Optical rotatory power (ρ = ± 5°35′/mm for λ = 6328 Å) was found in the Czochralski-grown ferroelectric crystal 5PbO·3GeO2. Reversal of the ferroelectric spontaneous polarization Ps caused the enantiomorphic transformation of the crystal and consequently the change in the sign of the optical rotatory power. The gyrati…

Geophysics and Sensor TechnologySolid-state spectroscopy and crystallographyMolecular spectroscopy and chirality

Effect of Scattering on the Attenuation of X Rays

J. J. DeMarco、P. Suortti1971-08-15Physical review. B, Solid state

The contribution of scattering to the total attenuation coefficient for x rays is considered in crystalline materials. Calculated values of the coherent-scattering coefficient for four commonly used wavelengths and for a number of cubic elements from $Z=6$ to $Z=42$ are presented. Measured attenuation of $\mathrm{Mo}K…

X-ray Diffraction in CrystallographyRadiation Shielding Materials AnalysisNuclear materials and radiation effects

X-ray study of L-arginine HCl, L-cysteine, DL-lysine and DL-phenylalanine

B. Khawas1971-08-15Acta Crystallographica Section B

Preliminary crystal-structure data for L-arginine HCI,, L-cysteine, DL-lysine and DL-phenylalanine have been derived from an analysis of their powder patterns. L-arginine HC1, crystallized from water, is tetragonal; a= 13-95 (4), c= 10.57 A, space group P422 and Z=8. L-cysteine and oL-phenylalanine are monoclinic. L-c…

X-ray Diffraction in CrystallographyAnalytical Chemistry and ChromatographyCrystallography and molecular interactions

Raman Spectra and Lattice Dynamics of α-Berlinite (AlPO4)

J. F. Scott1971-08-15Physical review. B, Solid state

Using the Born-von Karman and rigid-ion models of Elcombe for the optical phonons in $\ensuremath{\alpha}$-quartz, we have analyzed the Raman spectra of isomorphic AlP${\mathrm{O}}_{4}$ (berlinite). The resulting analysis yields several physical parameters which are not accessible to any other experimental measurement…

Glass properties and applicationsQuantum optics and atomic interactionsLuminescence Properties of Advanced Materials

Filamentary Conduction in VO2 Coplanar Thin-Film Devices

J. Duchêne、M. Terraillon、P. Pailly 等 4 位作者1971-08-15Applied Physics Letters

Filaments have been observed in VO2 coplanar thin-film devices and their I-V characteristic investigated. An analysis of the evolution of the temperature profile in the VO2 film is given.

Thin-Film Transistor TechnologiesGas Sensing Nanomaterials and SensorsTransition Metal Oxide Nanomaterials

Localized Effective Charges in Diatomic Crystals

G. Lucovsky、Richard M. Martin、E. Burstein1971-08-15Physical review. B, Solid state

We develop a model for simple diatomic crystals in which two effective-charge parameters are associated with the infrared-active optical-phonon mode. One of these is ${e}_{T}^{*}$, the macroscopic effective charge. The definition of the second charge, here designated as ${e}_{l}^{*}$, the localized effective charge, i…

Crystallography and molecular interactionsNonlinear Optical Materials ResearchSolid-state spectroscopy and crystallography