Semiempirical calculation of the atomic characteristics of the 2p5 3d, 4d, and 2p5ns (n = 3–10) configurations of neon

Semiempirical calculation of the fine-structure parameters, the intermediate-coupling wave functions, and the gyromagnetic ratios is carried out for a number of configurations of the neon atom in the single-configuration approximation. Comparative analysis of the results obtained is performed. __________ Translated from Optika i Spektroskopiya, Vol. 99, No. 4, 2005, pp. 558–561. Original Russian Text Copyright ? 2005 by Semenov, Kapel’kina, Tsygankova, Tsygankov.     

Total cross section for p−d breakup below 30 MeV

The total cross section for p−d breakup is studied in terms of the elastic -matrix through the unitary condition. Calculations using the complex Kohn variational method along with the Pair Correlated Hyperspherical Harmonic basis are presented. The results have been restricted to energies below E_p=30 MeV where Coulomb effects are expected to be sizable and are compared to the existing data. Two different measurements have been found in the literature: 40 years ago, Gibbons and Macklin [Phys. Rev. 114 (1959) 571] and 26 years ago, Carlson et al. [Lett. Nuovo Cimento 8 (1973) 319]. The calculations are found to be in reasonable agreement with these old data, though a discrepancy is observed near the deuteron breakup threshold. Moreover, a detailed analysis of the contributions to the observable from different partial waves has been performed. Unexpectedly, the main contribution for a wide range of energies has been detected in the J=3/2⁻ state.     

Dynamical spin susceptibility of the d–p model in the over doping region

Dynamical spin susceptibility χ^s(q,ω) of the d–p model in the over doping region is investigated by using the auxiliary boson technique. It includes higher order terms of the 1/N-expansion within the random phase approximation (RPA) of the local vertex, where frequency dependence of the quasi-particle interaction is taken into account. The incommensurate spin fluctuation is obtained due to the nesting effect in the low energy region (ωω^*), whereas the commensurate one in the high energy region (ωω^*), the characteristic energy ω^* is estimated to be about 30 meV. Both of the spin–lattice relaxation rate 1/T₁ and the spin–spin relaxation rate 1/T_g monotonically increase as T decreases, while the spin Knight shift K is almost independent of T.     

Quasi-particle excitations around a half-quantum vortex in p- and f- wave superconductors

Triplet superconductors such as Sr₂RuO₄ and Na_xCoO₂·yH₂O are now found to be p-wave (k_x ± ik_y) or f-wave ((k_x ± ik_y)cos ck_z) superconductors. Kee phenomenologically suggested that in these p-wave or f-wave superconductors, two half-quantum vortices (HQVs) become stable. Using Bougoliubov–de Gennes equation with the Fourier-Bessel expansion, we analyze quasi-particle excitations around an HQV at one end of the d-soliton for both p-wave and f-wave superconductors. We find that the bound state peak in the total local density of states around the HQV in f-wave superconductors becomes rather low compared to that around a singly quantized vortex. This is because, when flux and spin of the Cooper pairs are parallel, local density of states of quasi-particles shows bound state at zero energy. On the other hand, when flux and spin are anti-parallel, there is no phase singularity in the order parameter.     

Quark effects, meson-exchange currents and background in the d(e, e′p)Δ reaction

We have studied in detail the cross section for the d(e, e′p)Δ reaction leading to the emission of a fast nucleon and a Δ at rest, which has been advocated as a tool to investigate quark effects in nuclei. We find that ordinary meson-exchange currents mechanisms dominate the quark-exchange effects in the region of excitation of the Δ nd could be competitive at higher energies. Furthermore, at these higher energies, the small cross sections for the quark signal, together with the presence of a background about one order of magnitude bigger than the quark signal, make in any case the extraction of information about quark-exchange currents effects extraordinarily difficult.     

Spectra and multiplicities of n, p, d, t, K, π from antiproton annihilation in Cu and U

Inclusive energy spectra of neutrons, protons, deuterons, tritons, charged kaons and pions following antiproton annihilation at rest in copper and uranium have been measured. The determined multiplicity charged kaons is compared to recent measurements and indicates an enhancement of strangeness production. Ratios of directly emitted neutrons and protons have been determined for copper and uranium to 3.0±0.6 and 3.2±0.5, respectively.     

Theory of core-level spectroscopy in f and d electron systems

A review is presented of many body effects in core-level spectroscopy (CLS) of f and d electron systems from a theoretical point of view. Historical developments and the most recent topics in this field are described. The impurity Anderson model (IAM) has been successfully applied to the analysis of X-ray photoemission spectra (XPS) and X-ray absorption spectra (XAS) in f and d electron systems, where the f and d electron states are treated as being on a single atomic site and they are hybridized with valence or conduction electron states. The effect of a core-hole potential in the final state of CLS plays an important role. Typical examples of calculated results for XPS in rare-earth compounds and transition metal compounds are given. Recent developments in the study of resonant X-ray emission spectra (RXES) are also introduced. A theoretical approach beyond the IAM is discussed mainly for the analysis of RXES of transition metal compounds.     

Measurement of electron-muon correlations from semi-leptonic D decay in 200 GeV p + p collisions at RHIC-PHENIX

Charm production is a valuable probe of the early stages of a heavy ion collision. Correlated electron-muon pairs are a signature of semi-leptonic D decays, and a measurement of D mesons provides information on charm quark energy loss in the hot medium. The energy loss of heavy quarks is still not fully understood, so it is vital to investigate different decay channels of charm mesons to better understand this process. Measurements of electron-muon pairs suffer less from background than e ⁺ e ⁻ or μ⁺μ⁻ pairs since neither direct lepton production nor resonance decays produce this type of correlated signal. Another advantage is that because electrons are measured in the central arms and muons are measured in the forward region in PHENIX, open charm can be probed in a rapidity region different from previous dilepton measurements. Studying electron-muon pairs in p + p collisions provides an important baseline for the study of these processes in d + Au and Au + Au collisions. The data in this analysis was obtained during the 2006 RHIC run of p + p collisions at 200 GeV. The current status of this analysis will be presented.     

Extended q -euler numbers and polynomials associated with fermionic p -adic q -integral on Z p

The purpose of this paper is to construct extended q-Euler numbers and polynomials related to fermionic p-adic q-integral on ℤ _p . By evaluating a multivariate p-adic q-integral on ℤ _p , we give new explicit formulas related to these numbers and polynomials.     

Microscopic mechanisms of spin-dependent electric polarization in 3d oxides

We present a short critical overview of different microscopic models for nonrelativistic and relativistic magnetoelectric coupling including the so-called “spin current scenario”, ab-initio calculations, and several recent microscopic approaches to a spin-dependent electric polarization in 3d oxides.     

Magnetic flux structures of composite superconducting structures with d- and s-waves superconductors (d-dots)

Composite superconducting structures with d- and s-wave superconductors, d-dots, can be used as two state devices. Their functions depend on structures of the spontaneous magnetic field, which appears because of the anisotropy of d-wave superconductivity. Solving two-components Ginzburg–Landau equation, we have investigated magnetic field structures for d-dots with smaller and larger holes around the corners of d-wave superconducting region. And we argued the effect of holes on the magnetic structures.     

Processes of multiple scattering in the formation of M EELFS spectra of 3d metals

The processes of multiple scattering of a secondary electron from a local atomic structure and their contributions to the EELFS spectra have been considered. For the M EELFS spectra of 3d metals (i.e., the EELFS spectra behind the M edges of energy loss), the contributions of the processes provided by multiple processes of electron-impact excitation of 3d valence electrons have been analyzed.     

Local magnetic moment in the two-dimensional reduced p-d model

A two-dimensional reduced p-d model describing CuO₂ sheets in high-T_c oxides is studied by use of the composite operator approach. A set of self-consistent equations for the Green function is derived in a generalized mean-field approximation for the paramagnetic state. The results show a good agreement with the exact results obtained by numerical simulations on finite size lattices.     

Spin-other-orbit interaction in highly excited configurations with p and g electrons in outer shells

The matrix of the operator of the spin-other-orbit interaction energy is constructed for npn’g and np ⁵ n’g configurations. The matrix elements of this operator are calculated in the single-configuration approximation with wave functions in the LSJM representation and in the representation of uncoupled angular momenta using the known general formulas. The spin-other-orbit interaction is represented by three direct and three exchange radial Marvin spin interaction integrals.     

Theoretical analysis of ionic autoionization spectra of lanthanum via an intermediate state [Xe]5d6d 1P1

In the framework of multi-channel quantum defect theory, eigenquantum defects μα and the transformation matrices Uiα of La+ are calculated from first principles by relativistic multi-channel theory, while the dipole matrix elements Dα are obtained by fitting with experimental data. Then the ionic autoionization spectra of lanthanum via the inter-mediate state [Xe]5d6d 1P1 in the energy region of 90213-91905 cm-1 are obtained. Experimental peaks are classified and assigned by comparing with the corresponding calculated spectra. More specifically, four ionic autoionization Rydberg series converging to La2+ 5d5/2 2D5/2 and several states converging to higher lying states of La2+ are found and assigned.