Impact parameter dependence of the probability for removal of the 2s and 2p atomic electrons by nuclei

The probability W(x) of inner shell ionization by nuclei as a function of the impact parameter x is expressed through the ionization matrix element M_if. Values of W(x) for removal of the 2s and 2p electrons are calculated with the first Born M_if and compared with the SCA result.     

How to compare the SU(5) value of sin2θw with experiments?

We establish the relation between κsin²θ_w to be found from neutral-current experiments and sin²θ_w(Q) for Q=M_W predicted by grand unified theories. We then calculate sin²θ_W(M_W) in the minimal SU(5) model taking the M_W as well as M_x threshold effects into account. We find that these two threshold effects on sin²θ_W(M_W) cancel with each other and sin²θ_W(M_W)=0.211± 0.005.     

On the role of the higgs mechanism in present electroweak precision tests

Based on the observablesM _W, Γ _l ,s _W ^?2 (M _Z ² ), we evaluate the parameters Δx, Δy and ε at one-loop level within an electroweak massive vector-boson theory, which does not employ the Higgs mechanism. The theoretical results are consistent with the experimental ones on Δx, Δy, ε. The theoretical prediction for Δy coincides with the standard-model one (apart from numerically irrelevant terms which vanish forM _H→∞). Nonrenormalizability only affects Δx and ε, which differ from the standard-model results by the replacement logM _H→log Λ for a heavy Higgs mass,M _H (where Λ denotes an effective UV cut-off).     

Synthesis and physical properties of negative thermal expansion materials Zr1−xMxW2O8−y (M=Sc, In, Y) substituted for Zr(IV) sites by M(III) ions

Zr_1−xM_xW₂O_8−y (M=Sc, In and Y) solid solutions substituted up to x=0.04 for Zr(IV) sites by M(III) ions were synthesized by a solid-state reaction. X-ray diffraction experiments from 90 to 560 K revealed that all solid solutions had a cubic crystal structure and showed negative thermal expansion coefficients. The lattice parameters of Zr_1−xM_xW₂O_8−y were smaller than that of ZrW₂O₈ probably due to oxygen defects, though the ionic radii of substituted M³⁺ ions were larger than that of Zr⁴⁺. Order-disorder phase transition temperatures of the substituted samples drastically decreased in the order of Y, In and Sc compared to the percolation theory, and decreased with increasing M content.     

4f ground state properties of cerium in AuCu3 intermetallic compounds studied by x-ray absorption spectroscopy

L_III absorption edges of cerium in ternary AuCu₃ compounds Ce(Pd_1?xM_x)₃ (M = Ag and Rh) and (Ce_1?xY_x)Pd₃ are presented. We find that Ce in these compounds is mixed valent with n_f ? 0.7. The valence V of Ce(Pd_1?xRh_x)₃ becomes concentration independent of V = 3.29 ± 0.02 for x ? 0.18. In Ce_1?xY_xPd₃ we observe the valence to increase up to V = 3.32 ± 0.02 at the highest concentration of Y. We show, that a critical volume, available for the Ce atom, is associated with the concentration independent valence around 3.3. For both systems, linewidths W₁, W₀ and Δ = E(4f¹) ? E(4f⁰), as derived from L_III double-bump structure, are given. Possible falsifications due to “final states effects” on the valence are discussed.     

Gauge boson masses and lepton mixing inO(4)⊗U(1) gauge model

The Cabibbo angle is introduced as a mixing angle of the gauge bosonsW ^± andX ^± in anO(4)?U(1) gauge model. Masses of gauge bosons are calculated to beM _W=82 (input), \(M_z = \sqrt 2 M_W s\gamma = 130\) (γ is mixing angle, sin² γ=0.21),M _x=666, andM _Y=660, in units GeV. TheW _μ ^± andZ _μ ⁰ couple to the familiar charged and neutral currents, respectively. The effective neutrino oscillation angle is found to be the Cabibbo angle.     

Electron and hole injection in metal-oxide-nitride-oxide-silicon structures

The kinetics of electron and hole accumulation in metal-oxide-nitride-oxide-semiconductor structures is studied. Experimental data are compared with a theoretical model that takes into account tunnel injection, electron and hole capture by traps in amorphous silicon nitride SiN_x, and trap ionization. Agreement between experimental and calculated data is obtained for the bandgap width E _g = 8.0 eV of amorphous SiO₂, which corresponds to the barrier for holes Φ_h = 3.8 eV at the Si/SiO₂ interface. The tunneling effective masses for holes in SiO₂ and SiN_x are estimated at m _h ^* ≈ (0.4–0.5)m ₀. The parameters of electron and hole traps in SiN_x are determined within the phonon-coupled trap model: the optical energy W _opt = 2.6 eV and the thermal energy W _T = 1.3 eV.     

Similarity rules of magnetic minor hysteresis loops in Fe and Ni metals

We have studied similarity rules of quasistatic minor hysteresis loops for Fe and Ni single crystals in the wide temperature range from 10 to 600 K. Two similarity rules of M_R*/M_a*∼3/4 and W_R*/W_F*∼1/6, were found in a medium field range where irreversible movement of Bloch walls plays a crucial role for magnetization; M_a*, M_R*, W_F*, and W_R* are magnetization, remanence, hysteresis loss, and remanence work of a minor hysteresis loop. The similarity rules hold true, being almost independent of kinds of ferromagnets, applied stress, and temperature. The origin was discussed from the viewpoint of pinning effects due to dislocations as well as eddy current effects which become predominant at low temperatures for samples with low dislocation density.     

Optical-Information Transfer Through Perturbing Media and Determination of the Transfer Function

A version of the solution of the problem of simultaneous determination of the structure and characteristics of a two-dimensional signal and of two-dimensional complex transfer or instrumental functions is considered. The solution is based on measurements of four independent intensity distributions for spectral representation of a signal: I_sr(W_x, W_y) for a signal subjected to the transfer function, I_smrn(W_x, W_y) for a signal affected by additional specially produced modulation and the transfer function, I_srn(W_x, w_y) for a signal of the form I_sr(W_x, W_y) with a certain additional modulation at the output, and /₅mm(w_x,u/_y) for a signal of the form I_smr(W_x, W_y) with a certain additional modulation at the output. The intensity distributions obtained in the work make it possible to calculate the amplitude and phase components of the signal being analyzed and the transfer function. Additional modulations should provide visualization of phase information in one form or another.Linear amplitude modulation, which represents a particular form of spatial modulation, is analyzed. For this case, concrete expressions making it possible to calculate the amplitude and phase characteristics of the spectra of the signal being analyzed and the transfer function and, therefore, the characteristics of both the signal itself and the transfer function are obtained.     

Predictions for inclusive reactions based on a parton structure of hadrons

It is proposed that the asymptotic single-particle distributions f(x)=x(dσ/dx) in inclusive reactions should reflect the limiting longitudinal momentum distribution, ∼νW₂(x), of the hypothetical partons constituting a hadron. It is further argued that f(x) becomes, proportional to νW₂(x) as x → 1. Predictions are then made for a large class of inclusive reactions based on our knowledge of νW₂(x) from electroproduction data. For some of these (such as pp → π^±X), in which the predictions differ markedly from the Regge ones, present experiments distinctly favor ours.     

Electronic band structure and optical absorption of nanotubular zinc oxide doped with Iron, Cobalt, or Copper

The absorption spectra of the precursor-derived solid solutions Zn_{1 ? x} M _x O (M = Fe, Co, Cu) with a tubular morphology of aggregates have been investigated in the ultraviolet and visible regions. The maximum metal concentration x in the Zn_{1 ? x} M _x O solid solutions is 0.075 for iron, 0.2 for cobalt, and 0.1 for copper. It has been found that the optical absorption and the band gap of the Zn_{1 ? x} M _x O compounds depend on the type of dopant. The obtained experimental data have been interpreted using the results of the performed ab initio calculations of the electronic band structure and optical absorption.     

Higher order field equations II; Limit properties of green's functions

In a previous paper wave propagation was studied according to a sixth-order partial differential equation involving a complex mass M. The corresponding Yang-Feldman integral equations (indicated as SM-YF-equations), were formulated using modified Green's functions G^M_R(x) and G^M_A(x), which then incorporate the partial differential equation together with certain boundary conditions. In this paper certain limit properties of these modified Green's functions are derived: (a) It is shown that for |M| → ∞ the Green's functions G^M_R(x) and G^M_A(x) approach the Green's functions Δ_R(x) and Δ_A(x) of the corresponding KG-equation (Klein-Gordon equation). (b) It is further shown that the asymptotic behaviour of G^M_A(x) and G^M_A(x) is the same as of Δ_R(x) and Δ_A(x) - and also the same as for D_R(x) and D_A(x) for t→ ± ∞, where D_R and D_A are the Green n's functions for the KG-equation with mass zero. It is essential to take limits in the sense of distribution theory in both cases (a) and (b). The property (b) indicates that the wave propagation properties of the SM-YF-equations, the KG-equation with finite mass and the KG-equation with mass zero are closely related in an asymptotic sense.     

Morphological and chemical modifications and plume ejection following UV laser ablation of doped polymers: Dependence on polymer molecular weight

This work investigates the effect of polymer molecular weight (M_W) on the morphological and chemical modifications and on the plume ejection of doped polymethyl methacrylate (PMMA), and polystyrene (PS) films following irradiation at 248 nm. Micro-bubbles develop in the irradiated films of the low absorbing PMMA-based substrates. The extent and kinetics of the observed morphological changes are respectively larger and last longer in the low M_W polymer, as evidenced by optical microscopy and real-time monitoring of transmission of a CW laser. The changes observed in the Raman spectra upon irradiation indicate that degradation occurs to a higher extent in larger M_W polymers. Laser induced fluorescence (LIF) probing of the plume reveals the presence of NapH and PhenH products from, respectively, NapI- and PhenI-doped films and a slower ejection process in the plume of low M_W polymer. For highly absorbing PS, a less dramatic dependence on M_W is observed. Results are discussed in the framework of the bulk photothermal model, according to which ejection requires a critical number of bonds to be broken.     

Messungen zu den Vibrations- und Zweiquasiteilchenzuständen in172Yb

The Coster-Kronig and Auger spectrum of theL ₁ shell of gaseous argon has been investigated with an electrostatical spectrometer. The ionization in theL ₁ shell of argon was caused by electron impact. Absolute energies and relative intensities of all the Coster-Kronig and Auger transitions have been determined. The relative intensities of transitions within the groupsL ₁ L _{2, 3} M ₁,L ₁ L _{2, 3} M _{2, 3} andL ₁ MM agree fairly well with the theoretical values, calculated byRubenstein for extreme Russel-Saunders coupling, if intermediate coupling theory is used properly. Via the widthγ(L ₁) of theL ₁ level of argon, found in this experiment to be (1.84±0.2) eV, the following absolute group transition probabilities were determined (in units of 10¹⁴ sec^?1):W(L₁ L _{2, 3} M ₁)=(5.5±1.0),W(L₁ L _{2, 3} M _{2, 3})=(20.8±2.8),W(L₁ MM)=(1.44±0.16). The theoretical values are 21.0, 20.4 and 1.27. The possible reason for the large discrepancy between the experimental and theoretical value ofW(L₁ L _{2, 3} M ₁) is the use of the incorrect value of 287 eV for the binding energyE(L₁) byRubenstein. From the energies of theL ₁ MM transitions this value has been determined to beE(L₁)=(326.5±0.5) eV. This is the first direct measurement ofE(L₁) of argon.     

Perturbation theory for the effective interaction in nuclei

Starting from a decomposition of the Hamiltonian H(x) of the nuclear many-body problem in the form H(x) = H₀ + xV, where H₀ is a shell-model Hamiltonian, V the residual interaction, and x a strength parameter, we introduce a general effective interaction W(x) describing the interaction of nucleons within a shell, and the associated effective operators $\text{A}\text{?}\text{(x)}$. We display some properties of these operators. From a particular choice of W(x) we obtain the expressions introduced earlier by several authors. The convergence of the expansions for W(x) and $\text{A}\text{?}\text{(x)}$ in powers of x is investigated. It is shown that W(x) and $\text{A}\text{?}\text{(x)}$ are holomorphic in a domain of the complex x-plane including the point x = 0. With the help of a generalization of the von Neumann-Wigner noncrossing rule, we exhibit the nature of the common singularity of W(x) and $\text{A}\text{?}\text{(x)}$ which is closest to the origin and thus defines the radius r₀ of convergence of the expansions of W and $\text{A}\text{?}$. It is shown that r₀ is unaffected by the cancellation of unlinked diagrams. A criterion of consistency is established, which shows that most of the practical calculations of W lead to results which are inconsistent with the definition of W.     

Renormalization scheme dependence of electroweak radiative corrections

We compare two renormalization schemes of the electroweak standard model: the on-shell scheme withe, M _W ,M _Z ,M _H , and the fermion masses {m _f } as free parameters, and an intermediate scheme where theW boson self energy is renormalized atq ²=0 instead ofq ²=M _W ². TheM _W ?M _Z interdependence, and the differentiale ⁺ e ^?→μ ⁺ μ ^? cross section including polarized beams are calculated in both schemes to one-loop order. We find striking differences between the forward-backward asymmetries and the polarization asymmetries near theZ resonance after inclusion of weak and QED corrections.     

Effect of copper impurities on the absorption spectrum of thin films of superionic conductors MAg4I5 (M = K, Rb)

The absorption spectra of thin films of the solid electrolytes MAg₄I₅ (M = K, Rb) doped with copper (0 ≤ x ≤ 0.15) are studied in the spectral range 2–6 eV at temperatures of 90 and 290 K. It is established that the critical Cu content reaches x _crit = 0.05. A decrease in the Cu content to x ≤ 0.05 leads to the formation of MAg_{4 ? 4x} Cu_4x I₅ solid solutions, and the films remain spectrally stable. At x > 0.05, the films segregate into different phases: MAg_{4 ? 4x} Cu_4x I₅, Ag_{1 ? x} Cu_xI, and M ₂AgI₃.     

Ferromagnetic rare-earth and diamagnetic iron sublattices in ternary RFe0.67Ge1.33 type compounds

The magnetic properties of RM_2?xSi_x and RM_2?xGe_x where R = La, Ce, Nd, Sm, Eu and Gd and M = Fe, Co, Ni and Ag have been measured. It has been found that for samples of x = 0.4 both R and M sublattices are paramagnetically above 4.2δ K in the high spin state, whereas, if x = 0.67, R is magnetically ordered whereas M is diamagnetic.     

Luminescent properties of HTP AgGd1−xW2O8:Eux and AgGd1−x(W1−yMoy)2O8:Eux phosphor for white LED

Intense red phosphors, AgGd_1−xEu_x(W_1−yMo_y)₂O₈ (x=0.0-1.0, y=0.0-1.0), have been synthesized through traditional solid-state reaction and characterized by X-ray diffraction (XRD) and photoluminescence (PL). XRD results reveal that AgGd_1−xEu_xW₂O₈ synthesized at 1000 °C has a tetragonal crystal structure, which is named as high temperature phase (HTP) AgGdW₂O₈. All phosphors compositions with Eu³⁺ show red and green emission on excitation either in the charge-transfer or Eu³⁺ levels. Analysis of the emission spectra with different Eu³⁺ concentrations reveal that the optimum dopant concentration for Eu³⁺ is x=0.6 in the HTP AgGd_1−xEu_xW₂O₈ (x=0.0-1.0). Studies on the AgGd_0.4Eu_0.6(W_1−yMo_y)₂O₈ (y=0.0-1.0) and AgGd_1−xEu_x(W_0.7Mo_0.3)₂O₈ (x=0.0-1.0) show that the emission intensity is maximum for compositions with y=0.3 and x=0.5, respectively, and a decrease in emission intensity is observed for higher y or x values. The Mo⁶⁺ and Eu³⁺ co-doped AgGd(WO₄)₂ phosphors show higher emission intensity in comparison with the singly Eu³⁺-doped AgGd(WO₄)₂ in UV region. The intense emission of the tungstate/molybdate phosphors under 394 and 465 nm excitations, respectively, suggests that these materials are promising candidates as red-emitting phosphors for near-UV/blue GaN-based white LED for white light generation.