Structural transformations on Cu(110) under molecular iodine action

Interaction of molecular iodine with the Cu(110) surface is investigated by the methods of ultrahigh vacuum scanning tunneling microscopy (STM) and low energy electron diffraction (LEED). It is found that at the coverage θ =0.5 monolayer (ML) iodine forms a simple commensurate c(2×2) lattice. Further exposure of iodine leads to uniaxial compression of the c(2×2) lattice along the 〈110〉 direction of the substrate. The STM data indicate that compression of the iodine layer proceeds through formation of striped domain walls. As the coverage is saturated at θ = 0.63 ML, iodine forms a uniformly compressed quasi-hexagonal structure. Further exposure of iodine on the Cu(110) surface results in growth of a copper iodide film. STM images of thin (7 to 20 Å) CuI films reveal, in addition to atomic modulation, a superstructure with a period of 90 to 100 Å consisting of double stripes. A structure model of the copper iodide surface allowing for CuI lattice contraction and formation of double stripe domain walls is proposed.     

Weak four-fermion interaction in terms of SU(3) invariants. I

The four-fermion weak interaction is formulated in terms of invariants of the groups G₂=L?SU (2) and G₃=L?SU(3). The four-fermion Hamiltonian is constructed as a four-fermion invariant of the group G₃ on the basis of the spin tensorsψ _#x03B1;βγ ^lmn , whereα, β, γ=1, 2, 3, 4 are the spinor indices andl, m, n=1, 2, 3 are the unitary indices of the representation of G₃. It is shown that in the case of one multipletψ _#x03B1;βγ ^lmn one can construct one nontrivial invariant and in the case of two multipletsψ _#x03B1;βγ ^lmn and? _#x03B1;βγ ^lmn , nine nontrivial invariants. Of these, only in the case of two of the invariants, which contain two multiplets, are the lepton and baryon numbers conserved independently. One of these invariants is considered in detail. In the case of SU(2) there is no fundamental difficulty and a number of relations are obtained for the constants of the weak interactions and the probabilities of processes. In the case of SU(3) it is shown that the known breakings of SU(3) in weak interactions can be localized in the lepton octet by choosing it in a special way.     

Weak four-fermion interaction in terms of SU(3) invariants. II

A lepton octet is constructed by analogy with the baryon octet by the substitution p⁺N ₁e⁺,⁺₁ é⁺,^-₂^-, ^- N ₂^-, where ₁, ₂,N ₁,N ₂ are arbitrary constants. The neutral components are replaced by a linear sum of the electron and muon neutrinos with arbitrary coefficients. The constants are determined from the system of general conditions (normalization, absence of crossed terms of the type ( etc.). As a result, the lepton octet is determined to within a single constant, and this is shown to be identical with the Cabibbo angle. Calculations are also made of the weak decays of baryons of the octet in the case of both charged and neutral currents. In the case of charged currents, the results agree with Cabibbo's theory. Calculations are also made of the lepton-lepton weak interactions and the ratios of the corresponding constants are determined. The ratios are in qualitative agreement with the existing experimental data.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 1, pp. 51–56, January, 1976.     

A non-Abelian Higgs model on the lattice in terms of a complete system of gauge invariants

In this Letter we investigate the lattice version of a certain non-Abelian Higgs model, the theory of a SU(2)-gauge field interacting with a matter field in the adjoint representation.     

QED effective action in a constant electromagnetic field under conditions of possible Lorentz invariance violation in the Dirac equation

This paper is devoted to the calculation of corrections to QED effective action associated with the axial-vector condensate b ^μ, which violate the Lorentz invariance. It was shown that the linear in b ^μ contribution to the 1-loop effective action (Chern-Simons term) is absent in the case of a constant electromagnetic field. The contribution, which is quadratic in b ^μ, was calculated for the cases of both constant magnetic and electric fields. Asymptotic estimates of the quadratic in b ^μ term for strong and weak field strengths were obtained.     

Photoinduced transformations in a thin-film waveguide AgCl-Ag composition under a green (532 nm) laser beam

A linearly polarized (E ₀) laser beam (λ = 532 nm) causes photoinduced transformations in an AgCl-Ag composition consisting of a thin waveguide AgCl film on glass covered by a layer of Ag nanoparticles. Before the illumination the sample exhibits an absorption band due to localized plasmons in nanoparticles. The illumination excites plasmons and leads to scattering of waveguide TE₀ modes. The interference of modes with the incident light beam leads to the development of a periodic structure, the lines of which are formed by Ag particles and directed along E ₀. The measured structure period coincides with the result of calculation based on solving the dispersion equation for the TE₀-mode. Measurement of absorption in the E ‖ E ₀ polarization reveals dichroism and a spectral hole (at λ ≈ nm). It is shown that the structures formed remain on the substrate after removing AgCl in a fixing agent. The dichroism value and dispersion change after fixing. The character of dichroism prior to fixing is recovered after depositing an AgCl layer (with the parameters retained) on the fixed film.     

Structural changes in a heterogeneous solid (granite) under shock wave action

The structure of two granite types (plagiogranite and alaskite) before and after shock wave action has been studied by infrared, Raman, and photoluminescence spectroscopy methods. It has been found that the shock wave caused transformation of quartz and feldspar crystals composing these granites into diaplectic glasses.     

The action of SU(N) lattice gauge theory in terms of the heat kernel on the group manifold

We consider the heat kernel on the group manifold as an alternative to the Wilson action in lattice gauge theory, and we exhibit its strict analogy with the well-known Berezinski-Villain action. With the heat kernel action, the Gross-Witten singularity is rigorously absent in two dimensions. The similarity of the heat kernel action to the hamiltonian approach should provide a better convergence of the lagrangian strong coupling expansion, while its behaviour at weak coupling should simplify the analysis of the weak coupling perturbative expansion.     

SU(2) q in a Hilbert space of analytic functions

The algebraSU(2) _q is realized in a Hilbert spaceH _q ² of analytic functions; the starting point is the differential realization of operators that satisfyq-algebra in a Hilbert spaceH _q. The Weyl realization ofSU(2) _q is constructed exhibiting the reproducing kernel and the principal vectors; the noncommutativity of the matrix elements of a 2×2 linear representation ofSU(2) _q is obtained as consistency conditions for couplingj1=j2=1/2 toj=0, 1; the derivation of Clebsch-Gordan coefficients is sketched and theq-generalization of the rotation matrices is included. The unitary correspondence ofH _q with a Hilbert space of complex functions of a real variable is also studied. The study presented in this paper follows Bargmann's formalism for the rotation group as closely as possible.     

Comments on Chang and Torr's “dual properties of space time under an alternative Lorentz transformation”. comparison of Ether theory predictions with the result of a recent optical experiment

The dual properties of spacetime suggested by Chang and Torr are here analysed. The predictions of their ether theory are compared with the results of a recent optical experiment, which makes use of two crossed telescopes and a mirror, designed to detect the deviations of first order in v/c produced by the ether wind on the direction of starlight. If the observed deviations are due to experimental errors, special relativity is confirmed. If they are a real effect, most ether theories may be confirmed provided that the corresponding ether frame is assumed to be at rest with the sun.1. On sabbatical leave from: Departamento de Fisica, Facultad de Ciencias, Universidad de Los Andes, Merida, 5101 Venezuela this issue 4     

Dependence of a common effective action in a multidimensional R2 gravitation on the metric of the configuration space

A common effective action in a multidimensional R² gravitation on a plane R_d or R_k × T_d–k background is analyzed. The dependence of this effective action on the metric of the configuration space is studied.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 74–76, July, 1991.     

Effect of Lorentz local field correction on propagation of ultrashort laser pulse in one-dimensional para-nitroaniline (PNA) molecules

This paper investigates the effect of Lorentz local field correction (LFC) on the propagation of ultrashort laser pulses in a para-nitroaniline molecular medium under resonant and nonresonant conditions by solving numerically the full-wave Maxwell-Bloch equations beyond slowly-varying envelope approximation and rotating-wave approximation. The effect of the LFC is considerably obvious when pulses with large areas propagate in the dense molecular medium. In the case of resonance,the group velocity of the sub-pulses split from the incident pulse along propagation is severely decreased by the LFC,especially for the latest sub-pulse. However,in the case of nonresonance,the influence of the LFC on the temporal evolution of the pulse is less obvious and lacks homogeneity with an increase in incident pulse area,propagation distance and molecular density.     

Study on decays of DsJ *(2317) and DsJ(2460) in terms of the CQM model

Based on the assumption that D_sJ ^*(2317) and D_sJ(2460) are the (0⁺,1⁺) chiral partners of D_s and D^* _s, we evaluate the strong pionic and radiative decays of D_sJ ^*(2317) and D_sJ(2460) in the constituent quark meson (CQM) model. Our numerical results of the relative ratios of the decay widths are reasonably consistent with the data. PACS 13.25.Ft; 12.38.Lg; 12.39.Fe; 12.39.Hg     

Stäckel electrovacuum spaces with isotropic complete sets. Integration of field equations for the metric generalizing a space of type (1.1)

A system of Einstein-Maxwell equations is integrated for the metric that generalizes the metric of a space with full set of type (1.1). This is necessary for carrying out the classification of the corresponding Stäckel electrovacuum spaces. An algebraic classification of the solutions obtained is carried out.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 12, pp. 17–20, December, 1987.     

Luminescence of (Zn,Cd)Se,S-Cu phosphors under the simultaneous action of a sinusoidal voltage and ultraviolet radiation

Journal of Applied Spectroscopy -     

Photoinduced infrared activity in trans(CH)x: Inter[retation in terms of a lattice dynamical model

A lattice dynamical calculation for the photoinduced infrared vibrational modes is reported. By using the perturbed Green function method we have been able to compute the new frequencies and the integrated intensities of the photoinduced infrared modes at ω_1H⋍500 cm⁻¹, ω_2H⋍1260 cm⁻¹ and ω_3H⋍1370 cm⁻¹ in trans(CH)_x and at ω_1D⋍400 cm⁻¹ and ω_2D⋍1045 cm⁻¹ in trans(CD)_x. Most of the features of the photoinduced infrared spectra can be explained in terms of long conjugation length segment properties. Only the higher frequency tail of the band shape peaked at ω_1H and ω_1D can be related to the pertubbation determined by a photogenerated charge trapped in short segments. The calculated frequencies and integrated intensities are in good agreement with the experimental results.     

Intercalation of silver atoms under a graphite monolayer on Ni(111)

The process of silver intercalation under a graphite monolayer (GM) grown on the (111) nickel single-crystal face, GM/Ni(111), is studied. The experiments were conducted in ultrahigh vacuum. The systems were formed in situ in a vacuum chamber under direct monitoring of each stage in the formation of the systems by angle-resolved UV photoelectron spectroscopy and LEED. The possibility of silver intercalation in the GM/Ni(111) system was studied in the course of deposition of various amounts of the metal on the given subject with subsequent heat treatment. It was established that the process occurs optimally under cyclic alternation of the operations of adsorbate (Ag) deposition on the GM/Ni(111) surface and subsequent annealing of the system. In the intermediate stages of GM/Ag/Ni(111) formation, the GM on Ni(111) was found to exist in two phases. Ag intercalation under a graphite monolayer on Ni(111) at room temperature was verified.