Specific properties and spatial symmetry group of nonassociative spinor field

On the basis of nonassociative spinor field theory, the specific properties of a nonassociative spinor field are investigated. A new quantum number is introduced: the associator, which is a measure of the nonassociativeness of the field. To calculate the associator and spin in nonassociative algebra, open and closed products are introduced. It is shown that the spin consists of two components: the first half (calculated by the open-product rule) is similar to ordinary spin, while the second half (calculated by the closed-product rule) is attributed to the associator, i.e., is related to shear in the auxiliary isotopic space. The associator basis is expanded to a complete octonion basis, and the Poincaré group of four-dimensional space is expanded to a Poincaré group of eight-dimensional space. It is shown that, from these generators, in the particle rest system, the nonzero independent eigenvalues are: one, the sign of the particle energy, one of the spin components, one of the associator spatial components, and c₇. Tbilisi Medical Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 10, pp. 101–109, October, 1998.     

Influence of the thickness of the liquid layer on the ratio of the dimensions of a convection cell

A theory is developed for a new type of transition — a change in the ratio of the longitudinal and transverse dimensions of a convection cell as the thickness of a liquid layer is varied. A sudden change in the ratio of the cell dimensions takes place because of a change in the predominant mechanism for excitation of convection. The governing influence of buoyancy forces gives way to one of thermocapillary forces, and they in turn give way to the influence of thermoelectric forces for yet thinner layers. As the layer thickness is reduced gradually at a fixed external heating, the ratio of the dimensions will take on the values 0.7, 0.65, and 1, respectively. Zh. Tekh. Fiz. 68, 7–11 (November 1998)     

Hund’s Case (a)-case (b) transition in the singlet-triplet absorption spectrum of pyrazine in a supersonic jet

An analytic expression is derived for calculating the intensities of individual spin-rovibronic lines in the fully resolved gas phase electronic spectrum of a polyatomic molecule, in which one of the zero-order electronic states is a triplet state. The expression is employed to calculate the effect of fine structure splitting on the singlet-triplet absorption spectrum of pyrazine using the parameters available from experiment. A transition from Hund’s coupling Case (a) to Case (b) on going from low J to high J rotational levels is predicted to occur at a moderate resolution of a few hundred MHz. The effect is more pronounced in pyrazine-d ₄ and the pyrazine-argon van der Waals complex owing to their larger mass. Zh. éksp. Teor. Fiz. 114, 63–90 (July 1998) Published in English in the original Russian journal. Reproduced here with stylistic changes by the Translation Editor.     

Calculation of the noise factor of a traveling-wave gyrotron

The problem of calculating the noise factor of a traveling-wave gyrotron is solved for a model of a thin annular multistart-helical electron flux taking into account the effect of the quasistatic space-charge field. Plots of the gain and the noise factor of the traveling-wave gyrotron versus the electrical parameters of the amplifier are obtained. Zh. Tekh. Fiz. 68, 130–132 (February 1998)     

Investigation of surface topography, morphology and structure of amorphous carbon films by AFM and TEM

Morphology and structure of amorphous carbon films deposited with a pulsed arc source (LASER-ARC) have been studied using microscopical methods (SEM, TEM and AFM), electron diffraction and spectroscopical investigation (EELS). The parameters of the arc source and the deposition conditions (substrate temperature) influence morphology and structure of deposited amorphous carbon films. Especially the incorporation and growth of particles, embedded in the film have been investigated. By particle analysis using an optical microscope a majority of particles that is smaller than 500 nm has been determined. The morphology has been also demonstrated similar by AFM and TEM images. Their number and size of particles is strongly influenced by the deposition temperature. The structure of amorphous film is characterized by the EELS-spectra, but the particle structure was not detectable.     

Determination of the Tolman cone angle from crystallographic parameters and a statistical analysis using the crystallographic data base

Summary A new method of evaluating the Tolman cone angle from X-ray structural data available from the Cambridge Crystallographic Data Base has been developed and a statistical analysis of the cone angles of the phosphines PPh₃, PMe₂Ph, PMePh₂, PMe₃, PEt₃ and PCy₃ (Cy = cyclohexyl) in transition metal complexes has been completed.     

Spectroscopy of GaAs/AlGaAs microstructures with submicron spatial resolution using a near-field scanning optical microscope

A near-field scanning optical microscope (NSOM), which we built, is used to investigate 1–5-μm wide stripes with a 10-nm thick layer—a quantum well — on a GaAs surface. A map of the photoluminescence intensity is obtained synchronously with the topographic profile of the structures. The measured spatial distribution of the photoluminescence intensity is described satisfactorily in a model that takes into account carrier diffusion in the layer and the existence of a region with a short carrier lifetime near the side boundaries of the layer. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 7, 523–527 (10 April 1996)