类铷W37+离子双电子复合速率系数的理论研究

 利用全相对论组态相互作用理论方法,研究了类铷W³⁷⁺离子从基组态3s²3p⁶3d¹⁰4s²4p⁶4d经过双激发态(3s²3p⁶3d¹⁰4s²4p⁶4d)^-1nln′l′(n,n′=4,5)的双电子复合过程,得到了该离子在温度为1~5×10⁴ eV范围内的总双电子复合速率系数。分析比较了不同电子激发的双电子复合速率系数,结果表明:4p电子激发的双电子复合速率系数在低温时给出了主要贡献,而3d的贡献在高温时突出。由于强组态相互作用,两电子一光子跃迁对双电子复合速率系数的贡献不可忽略,其中辐射跃迁4p⁵4d5d5f-4p⁶4f5d的贡献是双激发态4p⁵4d5d5f总的双电子复合速率系数的5%。对双电子复合、辐射复合以及三体复合速率系数的比较表明,在所研究的温度范围内双电子复合速率系数最大。     

高离化态金离子的辐射复合及其退激发过程的理论研究

利用基于多组态Dirac-Fock方法的程序包GRASP92和RATIP以及最新发展的RERR06程序,详细计算了高离化态金离子(类镍Au51+、类铜Au50+和类锌Au49+)俘获一个自由电子到nl(n=4—8,l=0—3)壳层的辐射复合谱以及相应的辐射退激发谱.理论计算的辐射复合谱很好地重现了实验谱.研究结果表明:对类镍Au51+、类铜Au50+和类锌Au49+而言,将一个自由电子俘获到n=4壳层的概率最大;在辐射复合过程之后,处在n=4壳层的俘获电子的辐射退激发谱线最强,并且体现了整个辐射退激发谱的主要特征.     

Excitation of inner hole states in heavy nuclei with the (τ, α) reaction at 205 MeV

Energy spectra have been measured for the (τ, α) reaction at 205 MeV on⁹⁰Zr, ^118,124Sn and ²⁰⁸Pb. Results on the valence neutron shells and on the inner 1f_7/2 shell in ⁹⁰Zr, 1g_9/2 subshell in ^118,124Sn (T_< and T_> components) and 1h_11/2 subshell in ²⁰⁸Pb are presented.     

High resolutionL- andM-subshell internal conversion studies of low energy transitions in149Sm and151Eu

The internal conversion subshell intensities of the (21.529±0.014) keV transition in¹⁵¹Eu and the (22.494±0.011) keV transition in¹⁴⁹Sm have been determined in a high resolution investigation using a double-focussing iron-core spectrometer. The subshell ratios yielded unambiguousM1+E2 multipole mixtures for both transitions. δ²(E2/M1) for the 21.53 keV transition was determined to be (8.8±0.7)·10^?4 and for the 22.49 keV transition to be (5.5±1.2)·10^?3.     

Configuration mixing in Mo isotopes

An extension of the neutron-proton interacting boson model which takes into account the breaking of shell or subshell closures through two-particie-two-hole excitations is applied to the even-even Mo isotopes (Z = 42). In this calculation, ⁹⁰₄₀Zr₅₀ is taken as doubly magic and two-proton excitations across the subshell at Z = 40 are considered. Level spectra and electromagnetic properties are investigated. The results support the hypothesis of an interplay of two configurations in these isotopes.     

The conversion electron spectrum in the decay of195Au

Twenty-four internal conversion lines in the decay of¹⁹⁵Au have been studied at high resolution by means of the Vanderbilt iron-free spectrometer. The electron intensities of this work and previously published photon intensities were used to calculate the percentage decay to each level in¹⁹⁵Pt. Conversion coefficients andL subshell ratios were used to assign the following multipolarities: 30.8 keV, pureM1; 98.8 keV, (99±1)%M1; 129.8 keV, pureE2; and 210 keV, pureE2. MeasuredL subshell ratios are not in good agreement with theoretical values.     

Forming metastable carbon-rich anions in planetary atmospheres: the case of diacetylene

Alignment of the L ₃ ? (J = 3 / 2) subshell vacancy states in the Au, Bi, Th and U elements following photoinisation have been investigated through angular distribution measurements of subsequently emitted L ₃ subshell X-rays. The 59.54 keV unpolarised γ-rays from the ²⁴¹Am radioactive point-source were used to ionize the target and the subsequently emitted L X-rays were measured using an HPGe detector. The improved experimental procedure along with correct evaluation scheme permits straight-forward method for investigating anisotropy in photo-excited L X-ray emission. The efficiency of the detector and the absorption correction for the emitted L X-rays in the target remain fairly constant as the target-detector assemblage remains undisturbed in the present measurements at various angles. Isotropically emitted L ₁ subshell (J = 1 / 2) X-rays measured simultaneously were used to normalize the L X-ray spectra taken at different emission angles. The present measurements clearly support small theoretical predicted values of the alignment parameter; however, it is difficult to infer regarding the predicted anisotropic trends. The angular distribution measurements for the L ₃ subshell X-ray emission were also performed by placing the target in magnetic field  ～ 0.6 T. The earlier reported large anisotropy in angular distribution of the emitted L ₃ subshell X-rays and significant effect of external magnetic field on the angular distribution are ruled out.     

Photoionization cross sections for isoelectronic sequences of Ne,Ne+, Ne++

The evolution of the behaviour of photoionization cross sections relative to 2p subshell inside some isoelectronic sequences (Ne, Ne⁺, Ne⁺⁺) is pointed out, using a single electron model, with a central and non Coulombian potential.     

Calculation of the photoionization cross section of the 4d10 subshell of the La atom

The photoionization cross section of 4d¹⁰ subshell of La atom is calculated. The cross section curve near its threshold is strongly modified by rearrangement of outer shells in the process of photoionization.     

MICROSTRUCTURE ON COLLECTIVITY IN EVEN 116-122Xe ISOTOPES

Using microscopic interacting boson-fermion model formalism, the ground-band, β-band, γ-band and high spins states in even ^116-122Xe isotopes are successfully described. It can explain the recent experimental result that collective structures may coexist with the single-particle states and subshell feature. It predictes the energies of 1⁺ states.     

207Bi L-subshell orbital electron capture probabilities and decay energy

The L₁ subshell orbital electron capture probability P_L1 in the decay of 33.4 y ²⁰⁷Bi to the 2339.89 keV level in ²⁰⁷Pb is measured to be 0.518 ± 0.081 (95% confidence) by a new method in which L₁ subshell characteristic X-rays in the L_γ X-ray peak are observed in an Xγt coincidence mode with 1770.23 keV γ-rays. The value of P_L2is 0.047 ± 0.015 (95% confidence). From these results a value of Q_EC = 39_-8⁺²¹ keV is obtained for capture transitions to the 2339.89 keV level. The absence of K-capture to this level also is established by absence of K X-rays in coincidence with 1770.23 keV γ-rays.     

The deformation of the ground and excited states in the Ag and Sn nuclei

The microscopic calculation of the potential energies in the ground and excited states of Ag and Sn nuclei has been performed. The single particle Nilsson potential and the shell correction Strutinski method have been used. The weak sensitivness to nonaxial deformation has been found for even neighbours of these nuclei. The small tendency towards prolate deformation of the ground and excited one-quasiparticle states originating from theg _9/2 proton subshell in^101–105Ag odd isotopes has been noticed. The behaviour with quadrupole e and hexadecapole ε₄ deformation of the ground and two-quasiparticle excited 0⁺ states originating from thed _5/2,g _9/2 andg _7/2 proton subshells andh _11/2 neutron subshell in^112–118Sn has been investigated. The small quadrupole deformation of the excited 0⁺ states has been found what is in agreement with the experimental data concerning the rotational bands build on the first excited 0⁺ states in Sn isotopes.     

Photoionization cross-section calculations for 4d10 subshell of In in the RPAE

Photoionization cross-section and angular distribution of photoelectrons for 4d¹⁰ subshell of In are calculated in the Random Phase Approximation with Exchange (RPAE). The cross section is in satisfactory agreement with the recent experimental data by Stanford synchrotron.     

The observation of excited states in 142Gd and 142,144Dy

Levels in the neutron deficient ¹⁴²Gd and ^142,144Dy nuclei have been identified using multiple particle-gamma coincidence techniques. The isotopes were produced in the ^54,56Fe + ⁹²Mo and ⁵²Cr + ⁹⁶Ru reactions at 20–30 MeV above the Coulomb barrier. The new data are discussed in the context of the systematic trend toward deformation in light rare-earth nuclei and the disappearance of the Z = 64 subshell gap.     

The effect of many-electron correlations on the alignment of ions in atomic photoionization

It is shown that the inclusion of many-electron correlations and electron shell rearrangement can significantly change the alignment of the ion arising from the photoionization of atomic subshells with $\text{j >}\text{1}\text{2}$. The degree of alignment for photoionization of the 4d¹⁰ subshells of Xe, Cs and Ba atoms and the 5p⁶ subshell of Ba is calculated.     

Continuum and discrete states in the 3d photoabsorption spectra of Xe-like ions

The 3d subshell photoabsorption spectra of the Xe-like ions I^?, Cs⁺, Ba²⁺, and La³⁺ in a number of ionic solids have been measured. The spectra exhibit two different kinds of structures (due to 3d-4f resonances and delayed maxima of the 3d-εf continuum) and indicate that the 4f orbits in the 3d⁹4f configuration have collapsed in Cs⁺ and Ba²⁺.     

Angle- and spin-resolved photoelectron spectroscopy of the Hg 5d 10 subshell

Parameters describing electron spin polarization in Hg 5d ¹⁰ subshell photoionization have been measured at rare-gas resonance wavelengths between 73.59 nm and 30.38 nm. The spin parameters as well as asymmetry parameters β of a recent measurement are discussed in comparison with both nonrelativistic and relativistic ab initio calculations of several authors. The importance of many-electron correlations and spin-orbit coupling effects is considered.     

Magnetic moments of the 2 1 + states in102, 104Mo

Theg factors of the first excited 2⁺ levels in the neutron-rich nuclei¹⁰²Mo and¹⁰⁴Mo have been studied through the measurement of the perturbed angular correlations for theγ-γ cascades between the 0 ₂ ⁺ -2 ₁ ⁺ -0 ₁ ⁺ level sequences. The results of g=0.42±0.07 for¹⁰²Mo and ofg= _?0.11 ^+0.12 for¹⁰⁴Mo agree with the prediction of the vibrational-rotational model. In terms of IBA, with the assumption ofN _π=3 for the Mo isotopes which takes into consideration a two particle, two-hole excitation across the Z=40 subshell, the proton-bosong factor is deduced to beg _π=1.00±0.23. It is shown that this value provides evidence for subshell effects in¹⁰⁰Zr.     

Photoionization cross section of 4d10 Xe,Cs and Ba subshells with account of electron shell rearrangement

It is demonstrated that the account, along with many-electron correlations in RPAE method, of the electron shell rearrangement in the process of photoionization, permits to achieve a reasonable agreement between theory and experiment for the 4d¹⁰ subshell cross sections of Xe, Cs and Ba atoms.