Calculated conversion rate of E′4 centers into E′2 centers in alpha quartz

Recent cluster calculations by Rudha et al. [1] are used to obtain a pseudo-Jahn-Teller adiabatic energy profile for the interconversion between E′₄ centers and E′₂ centers based on the structural models proposed therein. Reasonable values are obtained for the underlying parameters which lends some further support to the models. A reaction rate method is next used to compute the temperature dependence of the conversion rate in either direction, as well as of the rate for reorientational flopping of Fowler's E′₁ center. Thermally-activated tunneling is found to be the main factor controlling the conversions in most of the temperature range of any practical interest.     

Thermal ionization decay of E′ centers in germanium dioxide

The thermally induced decay of oxygen-deficient E′ centers in GeO₂ glasses and ceramics has been studied experimentally and theoretically. The electron emission effect, which accompanies the thermally induced decay of these defects, has been interpreted based on the Perel’-Karpus model for the multiphonon ionization of centers in an electric field. It has been established that the decay of E′ centers in amorphous and crystalline modifications of GeO₂ is reversible and occurs according to the thermal ionization mechanism.     

Influences of neutral oxygen vacancies and E′_1 centers on α-quartz

Our calculations demonstrate that the concentration of neutral oxygen vacancies can affect the geometrical structrue,electronic structure, and optical properties of α-quartz. Moreover, the distribution of the neutral oxygen divacancy can also exert some influence on the properties of α-quartz. The dissimilarity and similarities are presented in the corresponding density of state(DOS) and absorption spectrum. In addition, when a higher defect concentration is involved in α-quartz,the influence of E1 center on the geometry of α-quartz becomes more significant. However, the introduction of an E1 center barely results in any improvement compared with the influence produced by the corresponding neutral defect.     

Spectral holeburning properties ofR′ color centers in LiF: dependence on doping and irradiation processes

The effects of doping and radiation-damage processes on the persistent spectral hole burning properties ofR color centers in LiF were studied using current tuned GaAlAs diode-laser derivative spectroscopy. Dopants used were Mg, Ni and Co and irradiation was done by x-rays and neutrons. The holes were alwys burned near the center of the zerophonon line. In most cases the experimentally determined hole lineshapes including side holes could be satisfactorily fit by a phenomenological lineshape model with three adjustable parameters. The amplitudes of the side holes relative to the main hole were found to increase with increasing radiation damage.     

Supersymmetry and Shape Invariance of Hartmann Potential and Ring-Shaped Oscillator Potential in the γ and θ Dimensions of Spherical Polar Coordinates

This article shows that in spherical polar coordinates, some noncentral separable potentials have super-symmetry and shape invariance in the r and θ dimensions, we choose Hartmann potential and ring-shaped oscillator astwo important examples, thus in principle the energy eigenvalues and energy eigenfunctions of such the potentials in ther and θ dimensions can be obtained by the method of supersymmetric quantum mechanics. Here we use an alternativemethod to get the required results.     

Kinetics of accumulation and decay of paramagnetic centers in γ-irradiated doped phosphate glasses

The dose dependences and decay kinetics of PO ₄ ^2? and PO ₃ ^2? paramagnetic centers and radiation-reduced europium Eu^(3+)? in γ-irradiated phosphate glasses of composition 4Na₂O · La₂O₃ · 7P₂O₅ doped with europium are studied. The data obtained are discussed within the trapping volume model in the approximation of short irradiation duration. It is shown that the trapping volume parameter v decreases with increasing irradiation dose. A physical interpretation of the parameter v is proposed.     

Formation of optical color and fluorescence centers in polytetrafluoroethylene under γ-irradiation

Fluorescent properties and colors of polytetrafluoroethylene (PTFE) samples were studied as functions of absorbed dose of γ-radiation at a temperature above the melting temperature of the crystallites (327°C) in the dose range 0.2–0.8 MGy. The samples were irradiated at low pressure (10^–6 Torr) in glass ampuls and at atmospheric pressure in a chamber purged with argon. Samples in ampuls acquired an off-white tint and fluoresced weakly. The fluorescence intensity increased slowly as the radiation dose increased from 0.2 to 0.6 MGy and decreased at 0.8 MGy. Samples irradiated in the chamber fluoresced more strongly and acquired colors that changed from gray (0.2 MGy) to dark-brown (0.8 MGy). Color centers were formed only in the sample surface layer. Their appearance was associated with the adsorption of particles of an unknown nature from the environment. The argon-purged samples turned white upon removing their surface layer (50 μm). The intensity and shape of fluorescence bands emitted by these samples remained essentially unaltered, i.e., depended weakly on the absorbed dose in the range 0.2–0.8 MGy.     

A New Type of Cascading Synchronization for Halo-Chaos and Its Potential for Communication Applications

Study of beam halo-chaos has become a key issue of concern for many future important applications. Control of halo-chaos has been researched intensively. This is the first time that the synchronization of beam halo-chaos has been realized in this field so far. Two nonlinear feedback control methods are proposed for the cascading synchronizing halo-chaos in coupled lattices of a periodic focusing channel. The simulation results show that the methods are effective. The realization of the synchronization of beam halo-chaos is significant not only for halo-chaos control itself but also for halo-chaos-based secure communication which may become an innovative technique.     

Gamma ray induced sensitization of 110°C TL peak in quartz separated from sand

We have investigated the gamma ray induced sensitization of the 110°C TL peak in quartz, separated from sand, in the dose range 30–750 Gy. A pre-dose of 100 Gy followed by annealing at 500°C for 1 h yielded an optimum sensitization factor of 14.2 for a test gamma dose of 0.5 Gy; this factor decreases slowly up to the studied pre-gamma dose of 750 Gy. From ESR studies carried out in the temperature range 25–550°C, the formation of E′₁-centres and their subsequent decay (at temperatures >400°C) have been observed. The released charge carriers (electrons) may lead to elimination of competitors (as a result of their filling up). Thus, the radiation-induced sensitization of the 110°C TL peak could be due to elimination of the competing deep traps.     

The potential for which E n 1 ′ 12=E n 2 ′ l1 in nonrelativistic quantum mechanics

The answer is provided to the question ‘What is the potential for which E _{n 1} ^′ l₂=E _{n 2} ^′ l₁ in nonrelativistic Quantum Mechanics?’     

Z′ mass limits,masses and coupling of higgs bosons,and Z′ decays in an E6 superstring based model

We demonstrate that current phenomenological constraints on Z-Z′ mixing for an E₆ grand unified group with low energy gauge group SU(2)_L×U(1)_Y×U(1)_Y, allow only a narrow range of Higgs vacuum expectation values consistent with possibilities favored by renormalization group expectations. Modest improvements in bounds on this mixing will lead to substantial bounds on the Z′ mass if alternative renormalization group solutions are not found. We then explore the constraints upon relations between Higgs masses in this model. In addition we explore the couplings of these Higgs to the gauge particles of the theory and emphasize the associated implications for Higgs detection in decays of the Z′.     

Photometric and fluorimetric study of the acid-base behavior of 2,2′-diquinolyl and 2,2′,2″-terpyridyl

A photometric and fluorimetric study of the acid-base behavior of 2,2-diquinolyl and 2,2,2-terpyridyl was performed. In sulfuric acid medium, the doubly charged 2,2-diquinolynium ion undergoes the first dissociation atH ₀=0.20±0.09, as determined by fluorimetry (_ex=336 nm, _em=424 nm). Photometric titration is less accurate because of the overlapping of the absorption spectra. The second dissociation constant of 2,2-diquinolyl was determined by fluorimetric titration (_ex=336 nm, _em=420 nm), obtaining a value of 3.67±0.03. The triply charged 2,2,2-terpyridyl molecule was found to undergo the first dissociation atH ₀=–7.17±0.04, as determined by fluorimetric titration (_ex=316 nm, _em=350 nm), in aqueous sulfuric acid medium. Photometric titration (=335 nm) was performed in the presence of 6.5% ethanol because of the low solubility of the compound in water. In this ethanolicwater medium, a value of the dissociation constant atH ₀=–7.39±0.03 was calculated. The second dissociation constant was determined to be 2.81±0.12 by photometric titration at 285 nm, and values of 4.03±0.26 and 4.16±0.20 were found for the third dissociation constant by photometric titrations at 320 and 295 nm, in 10% ethanol, in close agreement with previously reported values. The fluorimetric titration profile obtained by exciting at 274 nm and measuring the fluorescence emission at 350 nm, in the zone betweenH ₀=–3 and pH=10, is complicated by the several equilibria involved.     

Dislocation centers in α-martensite formation and dual couplings of thinly-laminated martensite crystals

The spectrum of observable dual couplings of crystals of thinly-laminated martensite with habiti {3 15 10} is discussed within the framework of the concept of the dislocation formation of -martensite crystals. A spectrum of dislocation centers of formation arising together with the developing martensite crystal is proposed. Here it is essential to divide the arising dislocation centers of formation into two groups associated with different displacement mechanisms. This difference permits understanding of the difference in the frequency of observation of couplings and the introduction of the concept of a comb structure — a set of secondary parallel crystals of martensite, associated with the same initial crystal.Urals Forestry Institute. Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 6, pp. 64–67, June, 1994.     

Reduced Probabilities for E1 and E2 Transitions in Alternating-Parity Spectra of Heavy Even—Even Nuclei

Reduced probabilities for intra/interband E1 and E2 transitions to alternating-parity states of the yrast and first nonyrast bands in ¹⁵⁰Nd, ¹⁵⁴Sm, ^{154, 160}Gd, and ^{162, 164}Er lantanide and ²³²Th and ^236,238u actinide nuclei are studied. The values calculated for B(E1) and B(E2) are compared with available experimental data. Variations in the surface deformation of nuclei upon a collective excitation are taken into account.