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Title: Properties of the 0{sub 2}{sup +} state and isospin excitation in the N=Z nucleus {sup 68}Se

Abstract

Band structure and electromagnetic transition properties of the low-lying states in the N=Z {sup 68}Se nucleus were studied within the framework of interacting boson model 3. The isospin excitation states with T>T{sub Z} are identified. The M1 and E2 matrix elements for low-lying states have been investigated and were used to identify the low-lying mixed symmetry states. Special attention is given to the occurrence of 0{sub 2}{sup +} state, recently predicted by the projected shell-model (PSM) calculation. The present predicted spectrum for {sup 68}Se is close to the recent PSM results and confirms the results for the 0{sub 2}{sup +} state. The calculated results are compared with available experimental data, and they are in general good agreement.

Authors:
; ;  [1];  [2]
  1. Key Laboratory for Quantum Information and Measurements and Department of Physics, Tsinghua University, Beijing 100084 (China)
  2. (China)
Publication Date:
OSTI Identifier:
20995278
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. C, Nuclear Physics; Journal Volume: 75; Journal Issue: 5; Other Information: DOI: 10.1103/PhysRevC.75.054316; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; EXCITATION; INTERACTING BOSON MODEL; ISOSPIN; MATRIX ELEMENTS; SELENIUM 68; SPECTRA; SYMMETRY

Citation Formats

Al-Khudair, Falih H., Li, Y. S., Long, G. L., and Center of Nuclear Theory, Lanzhou National Laboratory of Accelerators, Lanzhou 730000. Properties of the 0{sub 2}{sup +} state and isospin excitation in the N=Z nucleus {sup 68}Se. United States: N. p., 2007. Web. doi:10.1103/PHYSREVC.75.054316.
Al-Khudair, Falih H., Li, Y. S., Long, G. L., & Center of Nuclear Theory, Lanzhou National Laboratory of Accelerators, Lanzhou 730000. Properties of the 0{sub 2}{sup +} state and isospin excitation in the N=Z nucleus {sup 68}Se. United States. doi:10.1103/PHYSREVC.75.054316.
Al-Khudair, Falih H., Li, Y. S., Long, G. L., and Center of Nuclear Theory, Lanzhou National Laboratory of Accelerators, Lanzhou 730000. Tue . "Properties of the 0{sub 2}{sup +} state and isospin excitation in the N=Z nucleus {sup 68}Se". United States. doi:10.1103/PHYSREVC.75.054316.
@article{osti_20995278,
title = {Properties of the 0{sub 2}{sup +} state and isospin excitation in the N=Z nucleus {sup 68}Se},
author = {Al-Khudair, Falih H. and Li, Y. S. and Long, G. L. and Center of Nuclear Theory, Lanzhou National Laboratory of Accelerators, Lanzhou 730000},
abstractNote = {Band structure and electromagnetic transition properties of the low-lying states in the N=Z {sup 68}Se nucleus were studied within the framework of interacting boson model 3. The isospin excitation states with T>T{sub Z} are identified. The M1 and E2 matrix elements for low-lying states have been investigated and were used to identify the low-lying mixed symmetry states. Special attention is given to the occurrence of 0{sub 2}{sup +} state, recently predicted by the projected shell-model (PSM) calculation. The present predicted spectrum for {sup 68}Se is close to the recent PSM results and confirms the results for the 0{sub 2}{sup +} state. The calculated results are compared with available experimental data, and they are in general good agreement.},
doi = {10.1103/PHYSREVC.75.054316},
journal = {Physical Review. C, Nuclear Physics},
number = 5,
volume = 75,
place = {United States},
year = {Tue May 15 00:00:00 EDT 2007},
month = {Tue May 15 00:00:00 EDT 2007}
}
  • The reaction of (triphos)RhCl(/eta//sup 2/-CSe/sub 2/) (1) in CH/sub 2/Cl/sub 2/ with PEt/sub 3/ gives the phosphoniodiselenoformate complex (triphos)RhCl(Se/sub 2/CPEt/sub 3/) (2). Compound 2 reacts at room temperature in CH/sub 2/Cl/sub 2/ solution with dioxygen to yield OPEt/sub 3/ and (triphos)RhCl(Se/sub 2/CO) (3). The chloride ligand can be removed from 3 in CH/sub 2/Cl/sub 2/ by NaBPh/sub 4/ in 1-butanol to give the 16-electron complex ((triphos)Rh(Se/sub 2/CO))BPh/sub 4/ x 0.5CH/sub 2/Cl/sub 2/ x 0.5C/sub 4/H/sub 9/OH (4), which photochemically or thermally undergoes the chelotropic elimination of CO to form the bis(..mu..-diselenium) complex ((triphos)Rh(..mu..-Se/sub 2/)/sub 2/Rh(triphos))(BPh/sub 4/)/sub 2/ x 2DMF (5b).more » The crystal structures of 4 and 5b have been determined by x-ray crystallography and the results are presented here. The structure consists of monomeric complex cations ((triphos)Rh(Se/sub 2/CO))/sup +/, BPh/sub 4//sup -/ anions, and some amount of CH/sub 2/Cl/sub 2/ and 1-butanol molecules of crystallization. The metal atom is five-coordinated by the three phosphorus atoms of triphos and by the two selenium atoms of the diselenocarbonate ligand in a distorted-square-pyramidal environment. The structure consists of binuclear ((triphos)Rh(..mu..-Se/sub 2/)/sub 2/Rh(triphos))/sup 2 +/ cations, BPh/sub 4//sup -/ anions, and DMF molecules of crystallization. The system consists of two (triphos)Rh(/eta//sup 2/-Se/sub 2/) fragments related by a crystallographic inversion center. Each rhodium atom is coordinated by the three phosphorus atoms of triphos, an /eta//sup 2/-diselenium molecule, and one selenium atom from the other (triphos)Rh(/eta//sup 2/-Se/sub 2/) moiety. 27 references, 3 figures, 5 tables.« less
  • The reaction of InCl[sub 3] with Na[sub 2]Se[sub 5] in dimethylformamide (DMF) in the presence of Ph[sub 4]PCl gave (Ph[sub 4]P)[sub 4][In[sub 2](Se[sub 4])[sub 4](Se[sub 5])] (I) in 75% yield. Under the same conditions, InCl[sub 3] reacted with Na[sub 2]Se[sub 5] in the presence of Pr[sub 4]NBr or Et[sub 4]NBr and afforded (Pr[sub 4]N)[sub 4][In[sub 2](Se[sub 4])[sub 4](Se[sub 5])] (II) in 65% yield and (Et[sub 4]N)[sub 4][In[sub 2](Se[sub 4])[sub 4](Se[sub 5])] (III) in 72% yield, respectively. Single-crystal X-ray diffraction studies show that (I), (II), and (III) contain the same anion, [In[sub 2](Se[sub 4])[sub 4](Se[sub 5])][sup 4[minus]]. The anion consists ofmore » In[sup 3+] centers in trigonal bipyramidal coordination; each In atom is chelated by two bidentate Se[sub 4][sup 2[minus]] ligands forming a [In(Se[sub 4])[sub 2]][sup [minus]] unit. Two of these [In(Se[sub 4])[sub 2]][sup [minus]] units are bridged by an Se[sub 5][sup 2[minus]] chain forming a dimer. The hydrothermal reaction of InCl[sub 3] with Na[sub 2]Se[sub 4] in the presence of Pr[sub 4]NBr and water at 110[degrees]C for 3 days in an evacuated sealed Pyrex tube afforded deep red crystals of (Pr[sub 4]N)[sub 2][In[sub 2]Se[sub 2](Se[sub 4])[sub 2]] (IV), in 80% yield. Under the same conditions the reaction with [(Ph[sub 3]P)[sub 2]N]Cl yields [(Ph[sub 3]P)[sub 2]N][sub 2][In[sub 2]Se[sub 2](Se[sub 4])[sub 2]] (V) in 60% yield. Single-crystal X-ray diffraction studies show that (IV) and (V) contain the same binuclear anion [In[sub 2]Se[sub 2](Se[sub 4])[sub 2]][sup 2[minus]]. The reaction of InCl[sub 3] with Na[sub 2]Se[sub 5] in 1:2 mole ratio in acetonitrile in the presence of Et[sub 4]NBr afforded (Et[sub 4]N)[sub 3][In[sub 3]Se[sub 3](Se[sub 4])[sub 3]] (VI). Similar reaction of TlCl with Na[sub 2]Se[sub 5] in 1:2 mole ratio in DMF in the presence of Et[sub 4]NBr gave (Et[sub 4]N)[sub 3][Tl[sub 3]Se[sub 3](Se[sub 4])[sub 3]] (VII). 57 refs., 13 figs., 14 tabs.« less
  • Cross sections for excitation of the 3914-A (0, 0) band of the B/sup 2/summation/sub u//sup +/..-->..X/sup 2/summation/sub g//sup +/ transition of N/sub 2//sup +/ by proton impact on N/sub 2/ have been determined in the impact range from 100 eV to 6 keV. Cross sections for excitation of the B/sup 2/summation/sub u//sup +/ (v'=0) state are inferred from these measurements. The cross sections decrease by 2 orders of magnitude in a near-monotonic fashion in this energy range. Comparisons are made with total electron capture.
  • Results are reported from a calculation of the effective probabilities of electron--vibrational--rotational transitions when the state N/sup +//sub 2/B/sup 2/ ..sigma../sup +//sub u/(v' = 0) is excited by secondary electrons produced by ionization of nitrogen by a 10 keV primary electron beam. Use is made of the fact that the relative contribution from secondary electrons to emission from the first negative system of N/sup +//sub 2/ increases with distance from the center of the primary beam. The adiabatic approximation is used to calculate the transition probabilities from experimental data. It is shown that for secondary electrons, the probabilities of transitionsmore » with ..delta..k = 3, 4, 5,... are comparable in magnitude to the probabilities of transitions with ..delta..k = +- 1.« less
  • The crystal structure, electronic structure, and photoluminescence properties of Eu{sub x}Si{sub 6-z}Al{sub z-x}O{sub z+x}N{sub 8-z-x} (x=0-0.1, 0<z<1) and Eu{sub x}M{sub y}Si{sub 6-z}Al{sub z-x-y}O{sub z+x+y}N{sub 8-z-x-y} (M=2Li, Mg, Ca, Sr, Ba) have been studied. Single-phase Eu{sub x}Si{sub 6-z}Al{sub z-x}O{sub z+x}N{sub 8-z-x} can be obtained in very narrow ranges of x{<=}0.06 (z=0.15) and z<0.5 (x=0.3), indicating that limited Eu{sup 2+} ions can be incorporated into nitrogen-rich Si{sub 6-z}Al{sub z}O{sub z}N{sub 8-z}. The Eu{sup 2+} ion is found to occupy the 2b site in a hexagonal unit cell (P6{sub 3}/m) and directly connected by six adjacent nitrogen/oxygen atoms ranging 2.4850-2.5089 A. The calculatedmore » host band gaps by the relativistic DV-X{alpha} method are about 5.55 and 5.45 eV (without Eu{sup 2+} 4f5d levels) for x=0 and 0.013 in Eu{sub x}Si{sub 6-z}Al{sub z-x}O{sub z+x}N{sub 8-z-x} (z=0.15), in which the top of the 5d orbitals overlap with the Si-3s3p and N-2p orbitals within the bottom of the conduction band of the host. Eu{sub x}Si{sub 6-z}Al{sub z-x}O{sub z+x}N{sub 8-z-x} shows a strong green emission with a broad Eu{sup 2+} band centered at about 530 nm under UV to near-UV excitation range. The excitation and emission spectra are hardly modified by Eu concentration and dual-doping ions of Li and other alkaline-earth ions with Eu. Higher Eu concentrations can significantly quench the luminescence of Eu{sup 2+} and decrease the thermal quenching temperature. In addition, the emission spectrum can only be slightly tuned to the longer wavelengths ({approx}529-545 nm) by increasing z within the solid solution range of z<0.5. Furthermore, the luminescence intensity of Eu{sub x}Si{sub 6-z}Al{sub z-x}O{sub z+x}N{sub 8-z-x} can be improved by increasing z and the dual-doping of Li and Ba. - Graphical abstract: Excitation and emission spectra of Eu{sub x}Si{sub 6-z}Al{sub z-x}O{sub z+x}N{sub 8-z-x} with the project of a 2x2x2 supercell crystal structure viewed along (001), in which red spheres are the Eu atoms.« less