Light induced W5+ESR in WO3
After irradiation with infrared and visible light as 20K WO 3 single crystals show ESR attributable to W 5+ (5d 1 ) electrons trapped as polarons at lattice sites of the low-temperature WO 3 structure.
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GaP photovoltage transients
The photovoltage transients of GaP were examined with the retarding-potential electron-beam technique. Systematic changes in the signal size and shape were noted as the light intensity, chopping frequency, and wavelength were independently varied. The initial rise in the photovoltage signal was linear in light intensi…
The dynamic Peierls instability
A mean-field model of a one-dimensional conductor is shown in the presence of a fixed total current to exhibit a dynamic charge-density-wave (CDW) solution which can propagate without Landau damping at a temperature higher than ${T}_{c}$, the transition temperature for the static instability. However, the free energy…
Theory of phase transitions in solid methanes. X. Centering around Phase II in solid CH4
Thermal, spectroscopic, and other properties of methane solids, especially those concerning Phase II of solid CH4 in nuclear spin species equilibration, are theoretically studied from a unified point of view, i.e., the extended James–Keenan model. It assumes a rigid lattice and treats the molecular motions with respec…
Theory of dynamic light scattering from large anisotropic particles
The scattered electric field amplitude autocorrelation function of a dilute solution of large rigid anisotropic particles is computed in the Rayleigh–Debye approximation. The autocorrelation function for cylindrically symmetric particles is an infinite series of decaying exponentials with time constants τ−1l=q2D +l (l…
Determination of the valence band structure of InSe by angle-resolved photoemission using synchrotron radiation
The two-dimensional energy-band structure of the layer compound InSe has been determined directly from the polar-angle dependence of its photoemission spectra. The measurements were performed using synchrotron radiation in the photon energy range 15-29 eV. The measuring system consisted of two miniature plane-mirror a…
Monte Carlo simulation of anomalous transit-time dispersion of amorphous solids
Simple Monte Carlo multiple-trapping model simulations of the observed anomalous transit-time dispersion have been made. The model employs multiple trapping from an exponential distribution. Our results simulate the features of the experimental observations as well as provide a rational explanation for the transition…
Graphite intercalation compounds: Electronic properties in the dilute limit
A model is presented for the electronic properties of graphite intercalation compounds in the dilute limit, corresponding to intercalate concentrations more dilute than a stage-4 or -5 compound. In this limit, the electronic effect of intercalation in donor and acceptor compounds is modeled, respectively, as a raising…
Optical properties of polystyrene from the near-infrared to the x-ray region and convergence of optical sum rules
Optical properties of polystyrene in the form of thin films were determined for photon energies between 0.6 and 82 eV from transmission measurements. The results for $k$, the extinction coefficient, were combined with previous experimental results in the soft and hard x-ray regions up to 8050 eV. Analyses were made on…
Thermal properties of layered transition-metal dichalcogenides at charge-density-wave transitions
The heat capacity and resistivity at the charge-density-wave (CDW) transitions of several layered transition-metal dichalcogenides are presented. The magnitude of the thermal and resistive anomalies in the $2H$ polytypes indicates only a small fraction of the Fermi surface is involved in the CDW distortion. The transi…
X-ray photoelectron-spectroscopy study of oxides of the transuranium elements Np, Pu, Am, Cm, Bk, and Cf
Systematic x-ray photoelectron spectroscopy (XPS) measurements are reported for both core and valence electrons for oxides of the actinides thorium, uranium, neptunium, plutonium, americum, curium, berkelium, and californium. The XPS spectra of the localized $5f$ electron states were compared to the appropriate multip…
Hyperpolarizabilities of the nitroanilines and their relations to the excited state dipole moment
We have measured the second and third order hyperpolarizabilities of the three nitroaniline isomers and of two related molecules. For some isomers the intramolecular charge transfer is found to cause a very large enhancement of the second order polarizabilities. We present a theory relating this contribution to the fi…
Associated luminescence centres and traps in the thermoluminescence of CaF2:Dy (TLD-200)
The thermoluminescence glow curve of CaF 2 :Dy TLD-200 extends from room temperature up to about 450 degrees C. Dy 3+ is the main emitting centre for all the glow peaks. However, in addition to Dy 3+ emission, the glow peaks above 325 degrees C show four extrabands in the region 250-600 nm. Three of these are attribut…
Visual observation of phase domains in dysprosium orthoferrite
The coexistence of the ferrimagnetic and the antiferromagnetic phases has been observed in the DyFeO 3 orthoferrite. The observations were made in a polarization microscope by means of the Faraday effect. Several features of the spin reorientation which shed some light on the mechanism of the transition, have been obs…
Non-linear mechanical response of various metals. I. Dynamic and static response to simple compression, tension and torsion in the as-received and annealed states
The mechanical behaviour of some metals has been investigated experimentally for compressive, tensile and torsional loading cycles of about 120 and 370 mu s duration and for steady-state loading in each of the three modes of deformation. For the dynamic measurements the split Hopkinson bar technique has been used in t…
Decay of electrical charge on polyethylene films
The characteristics of the decay of the surface potential of corona-charged untreated polyethylene films 25 mu m thick in air have been investigated using a well-defined circular charging area and a high-resolution 80 mu m diameter induction probe. Distinct differences between the decay characteristics of negative and…
Dislocation Inertial Effects in the Plastic Deformation of Dilute Alloys of Lead and Copper
Strong experimental evidence is obtained that the maximum observed in the temperature dependence of the flow stress of copper alloys is a dislocation inertial effect. By using the superconducting effect in lead as a key, it is found that the maximum occurs when dislocations become critically damped.
Perovskite Oxides: Materials Science in Catalysis
In a time of growing need for catalysts, perovskites have been rediscovered as a family of catalysts of such great diversity that a broad spectrum of scientific disciplines have been brought to bear in their study and application. Because of the wide range of ions and valences which this simple structure can accommoda…
Microstructure of Defective Mink Guard Hair
Guard hairs from normal mink and from normal and defective areas of mink pelts with “singe” or “red hip” abnormalities were studied with the scanning electron microscope (SEM). The surface or cuticle of normal guard hair consists of scales overlapping each other. These cuticle cells show regional variation in shape an…
Untersuchung der Abreißbedingungen von Flüssigkeitstropfen durch einen auf eine Flüssigkeitsoberfläche auftreffenden Gasstrahl
Definition der Abreißbedingung durch das Kräftegleichgewicht am Flüssigkeitswulst. Messung der Gasgeschwindigkeit und der gasseitigen Grenzschichtdicke im Eindellungskrater. Daraus Berechnung der Reibungskraft sowie Berechnung der Schwerkraft und der Trägheitskraft. Ermittlung des kritischen Blaszustandes für den Begi…