Parity Configurations Research Articles

The 3p63d7 – 3p53d8 Transitions of Manganese-like Spectra Rb XIII and Sr XIV

Spectra of Rb XIII and Sr XIV have been studied in the region from 80 to 110Å by means of a triggered spark and a 3m-grazing incidence spectrograph equipped with a 3600 lines/mm holographic grating. Sixty-two lines in Sr XIV and 105 lines in Rb XIII are used to derive energy levels of the ground configuration 3p63d7 and of the first excited odd parity configuration 3p53d8. A parametric study by means of the chain of Cowan codes stresses the importance of configuration interactions (C.I.) within the Layzer complexes (3)15. Both the effective electrostatic C.I. parameters and the full complex treatment lead to a reduction of the large residual deviations noticed in earlier studies of 3p53d8 configurations of the sequence Y XV–Mo XVIII. Theoretical transition probabilities are reported for all classified lines.

Multi-charged acceptor centers in p-doped Si/Si 1− xGe x/Si quantum wells in the presence of a magnetic field

Neutral (A 0) and positively charged (A +) shallow acceptor centers in p-doped SiGe/Si nanostructures are investigated in the presence of an external magnetic field. The band mixing of valence states, the confinement potential and the magnetic field are responsible for an increase in the binding energy of the system. The properties of the lower-energy states of the A + are studied and their binding energies calculated for a Si 0.87Ge 0.13 quantum well. It is shown that the ground state of the A + complex has a singlet-like parity configuration up to magnetic fields as high as 12 T. The effects of hole–hole repulsive interaction and hole–impurity attractive potential on the A + spectra are considered.

Analysis of the and 5s5p6s configurations of four-times ionized iodine: I V

The spectrum of iodine was photographed in the 400-2100 Å region on a 3 m normal incidence spectrograph at the Antigonish laboratory using a triggered spark source. The , 5s5p5d and 5s5p6s configurations of four-times ionized iodine (I V) were identified for the first time in the In I isoelectronic sequence. 34 of the 35 possible levels of these odd parity configurations have been established. 176 additional lines have been classified in the I V spectrum. The relativistic Hartree-Fock and least-squares-fitting calculations were carried out using the Cowan code to interpret the observed spectrum. The new observations also lead to the revision of the levels to and respectively.

Fine structure analysis of the even parity configuration system of Ti I

Even-parity configuration system of Ti I has been considered on the basis of the experimental data available in literature. The fine structure analysis has been performed with the aid of a linked-parameter method of level-fitting calculations in a large multiconfiguration basis. Fine structure parameters have been determined and precise wavefunctions of even energy levels have been evaluated. Appropriate pseudorelativistic Hartree-Fock ab initio calculations of fine structure parameters have been presented for comparison purposes. Configuration interaction effects on even-parity configurations have been discussed.

Hyperfine structure studies of Tantalum

A narrow bandwidth ring dye laser pumped by an argon ion laser has been used to investigate the hyperfine structure of the even and odd parity levels of tantalum by optogalvanic spectroscopy in the wavelength range 5640 to 6050 A. Seventeen transitions have been observed and eight of these have not been reported in the literature so far. These transitions involve 27 levels with 15 odd and 12 even parity configurations. The magnetic dipole hyperfine interaction constants A and the electric quadrupole interaction constants B for these levels have been computed and compared with the data available in literature. The results for the levels at 34799.71 cm−1, 26960.46 cm−1 and 19657.78 cm−1 are reported for the first time.

Ioffe current constant of the Roper resonance from a relativistic three quark model

The Ioffe current constants for the proton and Roper resonance are evaluated using a linear confining potential model parametrized to reproduce the proton magnetic moment, spin, and energy. The three-body Dirac equation, for the ${(1/2}^{+}{)}^{3}$ positive parity configuration, is solved in hypercentral approximation. Quark masses of the order of 9 MeV are needed to reproduce the proton magnetic moment. When the proton rms charge radius and magnetic moment are reproduced, the Roper has an Ioffe coupling constant about 25% larger than the proton.

Spectroscopy of88Y homologous levels

The91Zr(\(z\bar p\),α)88Y reaction has been studied at incident energy of 22 MeV using a polarized proton source and a Q3D spectrometer. The differential cross sections and asymmetries for transitions to levels of88Y homologous to the lowest excitation energy states of87Y have been measured and interpreted both in terms of the experimental differential cross sections and asymmetries of the parent87Y states and by means of the finite-range distorted wave Born approximation theory using conventional Woods-Saxonα-particle potential. The advantage of the concept of homology consists in having to deal with a uniquel-transfer, that given by the transition to the corresponding parent state. In order to validate the concept of homology as a spectroscopic tool to identify spin, parity and dominant configuration of highly excited states in (\(z\bar p\),α) reaction on odd mass target nuclei, shell model calculations have been performed. Several new attributions of spin and parity for88Y residual nucleus are proposed.

Proton dipole form factor quark model

The dipole-shaped electromagnetic form factors of the proton may imply an exponential radial dependence of the wave function describing the charged constituents of the proton. The hypercentral potential required by the three-body Dirac equation to produce such an exponential radial wave function for three bound quarks is found to have a linear confining potential plus an attractive Coulombic central diagonal part. The configuration assumed for the quark constituents is the (1/2+)3 positive parity configuration, coupled to the spin of the proton. Assuming equal-mass Dirac quarks with no anomalous magnetic moments, we find the largest magnetic moment for this wave function to be 2.763 nuclear magnetons, close to, but less than the experimental value of 2.793. The hypercentral potential is mostly the sum of three quark-quark potentials, but a small three-body potential is required.

Ioffe current constant from a relativistic three quark model.

The Ioffe current constants for the proton are evaluated using a Poincar{acute e} invariant solution of the three-body Dirac equation, for the (1/2{sup +}){sup 3} positive parity configuration. Results are also compared to the QCD sum rule predictions and with the random instanton liquid model. {copyright} {ital 1996 The American Physical Society.}

Analysis of the 5s25p4, 5s5p5, 5s25p35d and 5s25p36s configurations of four-times ionized barium: Ba V

The fifth spectrum of barium was photographed in the 400-1220 AA region on a 3-metre normal incidence spectrograph using a triggered spark source. The earlier analysis of 5s25p4-5s5p5 transition array of Ba V has been confirmed. 42 out of 48 levels of the 5s5p5, 5s25p35d and 5s25p36s odd parity configurations have been established. The six unknown levels have J>or=4 which do not give any electric dipole transitions to the levels of the ground configuration. One hundred and thirteen new lines have been classified in Ba V spectrum. The least-squares-fitted (LSF) parametric and Hartree-Fock calculations were carried out and they interpret the level structure satisfactorily.

Analysis of the sixth spectrum of barium: Ba VI

The spectrum of barium was photographed in the 300 Å-1240 Å wavelength region on a 3-m normal incidence spectrograph at the Antigonish laboratory. The source used was a triggered spark. All five levels of the ground configuration 5s25p3 and 42 of 44 levels of the 5s5p4 + 5s25p25d + 5s25p26s configurations of Ba VI have been established. One hundred and twenty-seven lines have been classified. The parametric least-squaresfitted calculations involving configuration interaction amongst even parity configurations were carried out to interpret the observed spectrum satisfactorily.

Analysis of the 5s25p4-(5s5p5+5s25p35d+5s25p36s) transition array of trebly ionized caesium: Cs IV

The spectrum of caesium was photographed in the 300-1240 AA wavelength region on a 3 m normal incidence spectrograph. The earlier analysis of the 5s25p4-5s5p5 transition array of Cs IV was confirmed. The 5s25p4-(5s25p35d+5s25p36s) transition array has been investigated. 41 of 48 levels belonging to the 5s25p35d and 5s25p36s configurations have been established. One hundred and two additional lines have been classified in this spectrum. Configuration interaction calculations involving all three odd parity configurations have been carried out to satisfactorily interpret the observed spectrum.

Revised and extended analysis of five times ionized argon (Ar VI)

The spectrum of five times ionized argon, (Ar VI), has been observed in the 280-2100 Å wavelength range. Eighty-seven lines have been identified as transitions between levels of the 3s23p, 3s3p2, 3s23d, 3p3, 3s3p3d, 3s24s, 3s24d and 3s3p4s configurations. For 33 of the lines the classification is new. Forty-one energy level values belonging to these configurations were analyzed and we propose 9 new energy level values for levels corresponding to odd parity configurations. The configurations are interpreted by fitting the theoretical energy expressions to the observed energy levels using leastsquares techniques. The parameter values are compared with results from Hartree-Fock calculations.

Analysis of the 5d8-5d76p transition array of five times ionized thallium: TI VI

The spectrum of thallium was photographed in the 300-600 Å region on 10.7 m and 6.65 m grazing incidence spectrographs using a triggered spark source. In this region the 5d8-5d76p transition array of Tl VI was analysed. All but the highest 5d8 level (1S0) of the even parity configuration and 70 out of 110 levels of the odd parity configuration (5d76p) have been established. Two hundred and seven lines have been classified in this spectrum. Least squares fitted (LSF) and Hartree-Fock (HF) calculations have been carried out.

First direct calculation of 4f‘ 4f oscillator strengths for dipolar electric transitions in PrCl 3

In two previous papers, we interpreted completely the crystal field splitting and Zeeman data of trivalent praseodymium ions in PrCl 3 taking into account configuration interaction between 4f 2, 4f5d and 4f6p. The obtained eigenvectors are now used to calculate directly the oscillator strengths originating from dipolar electric processes between opposite parity configurations, giving rise to apparent 4f ‘4f transitions. The calculation reproduces in a satisfactory way the absorption from the ground levels toward the 3P 2 and 1D 2 multiplets but not toward 3P 0 and 3P 1.

Optical transition intensities of trivalent lanthanide ions in zinc and lead metaphosphate glasses

The Judd-Ofelt intensity parameters of the lanthanide ions Pr 3+, Sm 3+, Dy 3+, Ho 3+, Er 3+ and Tm 3+ in Zn(PO 3) 2 and Pb(PO 3) 2 glasses were evaluated from the absorption spectra. With the exception of Pr 3+, the ω 2 parameter is significantly lower in Pb(PO 3)2 than in Zn(PO 3) 2, as previously found for the Nd 3+ion, due to a weaker mixing with the opposite parity configurations. The monotonic dependence of ω 6, on the number of f electrons suggests that the mechanism responsible for the spectral intensities is mainly due to static distortions. The intensity parameters are in general higher than for other common oxide glasses.

Test of advanced hyperfine structure theory by precision radio-frequency and laser spectroscopy in molybdenum

The hyperfine structure splittings of 32 even parity states and of 26 odd partity states of molybdenum have been measured by atomic beam magnetic resonance and by laser induced fluorescence. The analysis of the hyperfine structure data of the even parity configurations (4d+5s)6 yields experimental evidence for second order hyperfine interactions. In addition, thegJ factors of 19 fine structure levels have been determined in order to test the quality of intermediate coupling wave functions for the (4d+5s)6 configurations.

The Spectrum of Four Times Ionized Scandium, ScV

The spectrum of four times ionized scandium emitted from a sliding spark discharge has been observed using a 3 m normal incidence spectrograph and a 5 m grazing incidence spectrograph. About 450 lines in the wavelength region 160 Å to 2200 Å have been identified as combinations between 46 odd levels belonging to the 3s23p5, 3s23p4 4p and 3s3p5 3d configurations and 72 even levels of the 3s3p6, 3s23p4 3d, 4d, 4s and 5s configurations. Of the previous identifications we have confirmed 18 levels. The level structure of the observed configurations has been theoretically interpreted by including configuration interaction effects. The inclusion of 3s23p33d2 in the calculations of the odd parity configurations is found to be important. Almost all levels of 3s3p5 3d show a considerable mixing with levels of 3s23p33d2, in some cases by as much as 50%. The energy parameters determined from least-squares fits to the observed level values are compared with Hartree-Fock calculations. The ionization energy is estimated to be 739 500 ± 1000 cm-1. (91.65 ± 0.12 eV).

Towards a shell model description of the low-energy structure of deformed nuclei I. Even-even systems

A microscopic shell model theory for the low-lying collective states of heavy deformed nuclei is described. Basis selection is guided by the Bohr-Mottelson-Nilsson picture of collective motion in nuclei. The necessary further truncation is achieved by exploiting an SU(3) symmetry inherent to the structure of the normal parity states and by restricting abnormal parity configurations to states with low seniority. An effective interaction comprised of operators which form an integrity basis for the SU(3) → R(3) algebra is shown to be sufficient to reproduce almost exactly, within a single leading irreducible representation of SU(3), the ground and gamma band rotational structure of eight rare earth ( 160Dy, 162Dy, 164Dy, 164Er, 166Er, 168Er, 166Yb, 168Yb) and four actinide ( 232Th, 234U, 236U, 238U) nuclei. The concomitant interband and intraband E2 strengths are also shown to be accurately reproduced. Extensions of the theory and necessary further theoretical investigations are reviewed.

Hypernuclear physics with pions

We investigate the possibility of producing hypernuclei with energetic pion beams via the (..pi../sup +/, K/sup +/) reaction. Due to the high momentum transfer involved (qapprox. =300 MeV/c), even in the forward direction, the (..pi../sup +/, K/sup +/) reaction preferentially populates high-spin natural parity configurations obtained by coupling a ..lambda.. particle to a neutron hole. We present differential cross section calculations utilizing the plane-wave approximation (PWA), the distorted-wave impulse approximation (DWIA) using fully distorted-waves, and the eikonal approximation (EIK) to approximate distortion effects. The DWIA and EIK results are in agreement, and lead to cross sections typically a factor of 5 --10 lower than the PWA results, due to absorptive effects. Cross sections of 5 --20 ..mu..b/sr at 0/sup 0/ are obtained in the DWIA for high-spin natural-parity ''stretched configurations,'' for example (/sub ..lambda../d/sub 3/2,5/2/x/sub n/ f/sub 7/2//sup -1/)/sub 5/- or (/sub ..lambda../f/sub 5/2,7/2/x /sub n/ f/sub 7/2//sup -1/)/sub 6/+ in /sub ..lambda..//sup 48//Ca, for pion lab momentum p/sub ..pi../ in the range 1.02--1.1 GeV/c, where the elementary cross section for K/sup +/n..--> pi../sup +/..lambda.. has its peak values. The cross sections for the population of the natural-parity ground-state levels (/sub ..lambda../S/sub 1/2/x/sub n/l/sub l/+1/2 /sup -1/)/sub J/=l with closed-shellmore » targets remain above 2 ..mu..b/sr at 0/sup 0/ for systems lighter than Aapprox. =50. The cross sections drop rapidly below p/sub ..pi../=1.02 GeV/c, due to threshold effects. Results are presented for the calculated quasielastic (quasifree) continuum background for the (..pi../sup +/, K/sup +/) reaction as a function of theta/sub 1ab/ and hypernuclear excitation energy. Because of the higher momentum transfer the quasielastic background is broader and significantly less in magnitude than that obtained in the (K/sup -/,..pi../sup -/) reaction at 0/sup 0/.« less