Calculating Fractional-Parentage Coefficients for Six Body System in Translational Invariant Basis

In this paper we present an independent scheme for constructing fractional parentage coefficients using symmetry group apparatus in translationally invariantmodel space, suitable for the six-particle system composed of three-particle bi-clusters, where the presented subsystems have their own intrinsic clusterization. Simple expressions for corresponding antisymmetrization procedure are presented as well as computational results.

     

Experimental determination of the chemical changes in the electron density on indium nuclei by the γ‐spectrometric ΔIγ/Iγ method

The γ‐spectrometry method for determination of the relative change Δλ_EC/λ_EC in the partial probability λ_EC for the ^114mIn decay branch by the electron capture (EC), when the nucleus is in different chemical environments, was developed. The method is based on an experimental determination of the relative change ΔI_γ/I_γ in the intensity of the γ‐radiation which is emitted by the excited daughter ¹¹⁴Cd nuclei after EC. The ^114mIn decay by EC in indium metal, In₂O₃ and InAs was compared. The largest ΔI_γ/I_γ=(2.5±0.8)·10⁻⁴ has been found for InAs relatively to In₂O₃. The chemical changes in the electron density on the indium nucleus corresponding to the measured ΔI_γ/I_γ values have been determined. This revised version was published online in July 2006 with corrections to the Cover Date.     

Method simplifying calculation of coefficients of fractional parentage for translationally invariant shell-model

A new procedure for large-scale calculations of the coefficients of fractional parentage (CFP) for many-particle systems is presented. The approach is based on a simple enumeration scheme for antisymmetric N particle states, and we suggest an efficient method for constructing the eigenvectors of two-particle transposition operator $P_{N_1 ,N}$ in a subspace where N ₁ and N ₂ = N ? N ₁ nucleons basis states are already antisymmetrized. The main result of this paper is that according to permutation operators $P_{N_1 ,N}$ eigenvalues we can distinguish totally asymmetrical N particle states from the other states with lower degree of asymmetry.     

Light energy accumulation using Ti/RuO2 electrode as capacitor

In the present study, the possibility to use Ti/RuO₂ electrode as capacitor for storage of photoelectrons generated under UV irradiation in Ti/TiO₂ photoelectrode has been investigated. A light-sensitive TiO₂ layer has been formed by means of anodizing Ti electrode in the solution of 0.5 M H₂SO₄. A layer of RuO₂, exhibiting the properties of electrochemical capacitor, has been formed by means of thermal decomposition of RuOHCl₃ also on Ti substrate. The photocharging capability of RuO₂ has been studied by means of short-circuiting Ti/RuO₂ electrode with Ti/TiO₂ photoelectrode in deaerated solution of 0.1 M KOH. It has been shown that the intensity of photocurrent flowing from Ti/TiO₂ to Ti/RuO₂ electrode depends mainly on the potential of the latter. Maximum value of photocurrent density was ∼180 μA cm⁻², which corresponded to maximum value of photon-to-electron conversion efficiency (IPCE) of about 60%. The amount of photogenerated charge Q _ph, which can be stored, depends on the capacitance of RuO₂ coating. Under the conditions of the experiment, Q _ph ranged from ∼35 to ∼50 mC, which corresponded to a specific charge of RuO₂ coating ranging between ∼20 and ∼30 mAh g⁻¹.     

Converging upper and lower bounds for ground-state energies of atomic nuclei

The production of K⁺-mesons in proton-nucleus collisions from 1.0 to 2.3 GeV is analyzed with respect to one-step nucleon-nucleon (NN NYK⁺) and two-step -nucleon (N K⁺YN) or pion-nucleon (N K⁺Y) production channels on the basis of a coupled-channel (CBUU) transport approach including the kaon final-state-interactions (FSI). Momentum-dependent potentials for the nucleon, hyperon and kaon in the final state are included as well as K⁺ elastic rescattering in the target nucleus. The transport calculations are compared to the experimental K⁺ spectra taken at COSY-Jülich. Our systematic analysis of K⁺ spectra from ¹²C, ⁶³Cu, ¹⁰⁷Ag and ¹⁹⁷Au targets as well as their momentum differential ratios gives a repulsive K⁺ potential of 20±5 MeV at normal nuclear matter density.     

Formation of cuprous oxide layers in Cu(II) solutions containing gluconic acid

In accordance with thermodynamic analysis, cuprous oxide layers are formed spontaneously in the Cu|Cu(II), gluconic acid system at pH > 3.7 under open-circuit conditions. A current peak of Cu₂O reduction is observed on cathodic voltammograms at ca −0.7 V, its height being dependent on the exposure time. The analysis of the charge transferred in this region yields the rate of Cu₂O formation equal to 1.25 × 10⁻¹⁰ mol cm⁻² s⁻¹. The light perturbation of Cu electrode under open-circuit conditions results in the generation of a negative photopotential, which is indicative of n-type conductivity. The threshold wavelength is equal to ∼590 nm and is consistent with a band gap of ∼2.1 eV. Anodic photocurrents, which are observed near the open-circuit potential, decrease with cathodic polarization and change their sign at ∼0.05 V. Analysis of impedance data was performed, invoking the equivalent circuit that accounts for the two-step charge transfer. In the presence of Cu₂O, some retardation of Cu(II) reduction was found to occur with a slight increase in the admittance of the double layer. The suggestion has been made that oxide layers formed in Cu(II) gluconate solutions cannot be compact and uniformly distributed over the entire electrode surface. Relevant investigations of surface morphology support this conclusion.     

Influence of laser microfabrication on silicon electrochemical behavior in HF solution

Influence of direct laser writing with femtosecond pulses on electrochemical etching of n-type low conductivity (>1,000 Ωcm) silicon is demonstrated. It has been shown that thermal 1-μm-thick SiO₂ layer on silicon surface can be used as a protective layer in the electrochemical etching process. It has been found that laser ablation changes not only the surface morphology and structure of silicon samples but also the character of their anodic etching in aqueous solution of hydrofluoric acid. Formation of microvoids and caverns of irregular shape has been observed at the laser-ablated sites. It is proposed that the change of silicon conductivity from n- to p-type takes place at the laser fabricated regions. Processes of Si anodic oxidation and electrochemical etching are discussed.     

Calculation of Coefficients of Fractional Parentage for Large-Basis Harmonic-Oscillator Shell Model

A new procedure for large-scale calculations of the coefficients of fractional parentage (CFPs) for a single j-orbit with isospin is presented. The approach is based on a simple enumeration scheme for antisymmetric A-particle states and an efficient method for constructing the eigenvectors of an idempotent matrix. We investigate the characteristics of the introduced CFP basis and the application of this procedure to the ab initio harmonic-oscillator shell-model approach. The results of CFP calculations for the j=1/2,…,41/2 orbits are presented (the full sets of one-particle and two-particle CFPs up to the j=9/2 orbit are obtained). The new computer code for calculation of the CFPs proves to be very quick, efficient, and numerically stable and produces results possessing only small numerical uncertainties.     

Effect of Ligands on Formation of Photosensitive Oxide Layers on Copper Electrode*

Photosensitive oxide layers are found to develop on copper electrode exposed to solutions containing Cu(II), different ligands, and K₂SO₄ as a supporting electrolyte. Two mechanisms of Cu₂O formation are discussed: corrosion of copper in naturally aerated Cu(II)-free solutions, and interaction between Cu and Cu²⁺ yielding intermediate Cu⁺ ions. Oxide layers formed in the supporting electrolyte at pH 5 and 7 exhibit n-type conduction; the n–p transition is observed at pH 10. An addition of ligands suppresses the oxide formation. The correlation between the photoelectrochemical effects and the stability of Cu(II) complexes is revealed: the higher the complexation degree, the lower the level of photoresponse. A model of nonuniform Cu₂O-containing layer with predominant n- and p-type properties at copper/oxide and oxide/solution interfaces, respectively, is discussed.