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1.
A new rotational band has been identified and assigned to 188Au for the first time using the 173Yb(19F,4nγ) reaction at the beam energies of 86 and 90 MeV. This band is proposed to be built on the πh9/2 νi13/2 configuration by comparing the band properties with known bands in neighboring nuclei. The prolate-to-oblate shape transition through triaxial shape has been proposed to occur around 188Au for the πh9/2 νi13/2 bands in odd-odd Au isotopes on the basis of total Routhian surface (TRS) calculations. 相似文献
2.
The 109,111,113Rh nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85 MeV. Their level schemes have been built from gamma-rays detected using the Euroball IV array. High-spin states of
the neutron-rich 111,113Rh nuclei have been identified for the first time. Several rotational bands with the odd proton occupying the π g
9/2, π p
1/2 and π( g
7/2/ d
5/2) sub-shells have been observed. A band of low-energy transitions has been identified at excitation energy around 2 MeV in
109,111Rh, which can be interpreted in terms of three-quasiparticle excitation, π g
9/2ν h
11/2ν g
7/2/ d
5/2. In addition another structure built on states located at low excitation energy (608 keV in 111Rh, 570 keV in 113Rh) points out that, as already observed in the lighter isotopes 107,109Rh, triaxial deformation plays a role in the neutron-rich Rh isotopes well beyond the mid-shell.
Received: 15 July 2002 / Accepted: 9 October 2002 / Published online: 3 December 2002
RID="a"
ID="a"e-mail: porquet@csnsm.in2p3.fr
RID="b"
ID="b" Present address: CSNSM IN2P3-CNRS and Université Paris-Sud 91405 Orsay, France.
RID="c"
ID="c" Present address: CEA/Saclay, DSM/DAPNIA/SPhN, 91191 Gif-sur-Yvette Cedex, France.
Communicated by D. Schwalm 相似文献
3.
High-spin states in 190Tl have been studied via the 160Gd(35Cl, 5nγ) reaction. The level scheme, consisting of the πh9/2(×)νi13/2 oblate band and a cascade with character of single particle excitations, has been established. Spin values have been firmly assigned to the oblate band in 190Tl, resulting in low-spin signature inversion in the πh9/2(×)νi13/2 oblate band for the first time. Based on the similarity of the level structure in doubly odd Tl nuclei, spin values for the oblate bands in 192―200Tl should be re-assigned, and a consistent low-spin signature inversion has occurred in these oblate deformed nuclei. The low-spin signature inversion phenomena can be interpreted qualitatively by using the 2-quasiparticle plus rotor model including p-n residual interactions. 相似文献
4.
High-spin states in 178Ir were investigated by means of in-beam γ-ray spectroscopy techniques using the multidetector array GASP. Excited states
of 178Ir were populated through the 159Tb( 24Mg, 5n) fusion-evaporation reaction at E( 24
Mg) = 131-141 MeV. Several rotational bands were observed. Among them, the π i
13/2⊗ν i
13/2 structure has been identified up to spin 36 ?. This band exhibits an anomalous signature splitting and a signature inversion
around spin 25 ?.
Received: 13 December 2000 / Accepted: 11 April 2001 相似文献
5.
Seven experimentally observed bands of 155Tb are analyzed in detail, using the particle-number-conserving method for treating the cranked shell model with monopole and quadrupole pairing interactions. We satisfactorily reproduce the experimental alignments and especially focus on the microscopic mechanism of the second back-bending and the influence of pair interaction on ultrahigh spins. Our calculated results show that the πi13/2 orbitals are too high to give a contribution to the moment of inertia below hω≈0.7 MeV. Instead, the crossing between the π[541]l/2 and other proton orbitals is responsible for the second back-bending. We assign a possible configuration to the decoupled band found in 155Tb and predict eleven bands which are experimentally unobserved. 相似文献
6.
High-spin states in 185pt have been reinvestigated via the reaction 173Yb(<'16>O, 4n) at a beam energy of 90 MeV. The previously known band based on the ν7/2<'->[503](f<,7/2>) Nilsson orbital has been extended to higher spin states. Properties of the ν7/2<'->[503](f<,7/2>) band have been discussed with an emphasis on the evolution of configuration while increasing the spin. 相似文献
7.
Spin splittings for several important atmospheric lines in the ν3 band of NO 2 have been measured by diode laser. An improved spin-splitting program has been developed which takes into account the asymmetry effects in the lower Ka splittings. The measured spin splittings and the derived spin-rotational constants are reported in this study to a much higher accuracy than previously achieved. 相似文献
8.
High-spin states in 185Pt have been reinvestigated via the reaction 173Yb( 16O, 4n) at a beam energy of 90 MeV. The previously known band based on the ν7/2 -[503](f 7/2) Nilsson orbital has been extended to higher spin states. Properties of the ν7/2 -[503](f 7/2) band have been discussed with an emphasis on the evolution of configuration while increasing the spin. 相似文献
9.
High-resolution diode laser spectra and medium-resolution F-T spectra of deuterated ammonia have been obtained in the 700- to 1030-cm −1 region. Out of about 800 lines measured by diode laser spectroscopy, approximately 500 lines have been assigned to the ν2 transitions of NH 2D. The parameters for the ground and ν2 states of NH 2D have been derived by the simultaneous analysis of the infrared and microwave data. The standard deviation for the IR data is ∼8 × 10 −4 cm −1. It is shown that the energy levels of NH 2D in the ν2 state are heavily perturbed by inversion-rotation interaction and that it is necessary to include higher order inversion-rotation interaction terms to obtain a satisfactory fit of the observed data. 相似文献
10.
High-Spin states of odd-odd 166Lu were populated using the 139La( 30Si,3n γ) 166Lu at a beam energy of 120 MeV. Twelve new γ-rays were placed on top of the previously known two rotational bands built upon πg
7/2⊗ νi
13/2 and πh
11/2⊗ νi
13/2. Extending high-spin states up to 21 + and 25 − for each band, we have observed the onset of band crossing near ħω
c ≈ 0.35 MeV. The band crossing frequency of the yrast πh
11/2⊗ νi
13/2 band is consistent with the neutron BC band crossing observed in lighter odd-odd Lu isotopes. 相似文献
11.
The effect of a-, b-, and c-axis Coriolis perturbations in the infrared spectrum of the band system ν10, ν7, ν4, ν12 of trans-d2-ethylene has been studied at a resolution near 0.03 cm −1. From a global analysis of this band system taking into account Coriolis resonances, spectroscopic constants for each of the vibrations are derived as well as second-order Coriolis interaction constants for ν10 and ν7. 相似文献
12.
High-spin states in 161Er have been studied experimentally via the 150Nd(16O, 5n) reaction at a beam energy of 86 MeV. Three rotational bands built on the 5/2+[642], 3/2−[521], and 11/2−[505] configurations have been extended up to high-spin states, and particularly, the α = −1/2 branch of the ground state 3/2−[521] band has been revised significantly. It is found that signature inversion occurs in the 3/2−[521] band after the band crossing in 161Er. The systematics of the signature inversion associated with the 3/2−[521] configuration in the rare-earth region is discussed. The band properties are analyzed within the framework of a triaxial particle-rotor model, and a triaxial deformation is proposed to the 3/2−[521] band. 相似文献
13.
The spectrum of the ν1 + ν2 band of NO 2 has been studied with a resolution of 0.025 cm −1. Spin-rotation constants and rotational constants are reported. An interesting perturbation has been found in the ground state of the molecule which occurs when the Ka = 0 and Ka = 2 levels become accidentally nearly degenerate around N = 42. An explanation of this interaction is presented. 相似文献
14.
Pressure-broadening parameters of 25 lines belonging to the ν1 band of 16O 12C 32S in collision with O 2 have been measured with a tunable diode-laser spectrometer. From these coefficients and previously measured N 2-broadening coefficients, smoothed values of air-broadening parameters of OCS have been derived. The experimental results for O 2 broadening are compared with values calculated on the basis of the Anderson-Tsao-Curnutte theory and an improved semiclassical impact theory in which we used a simple formalism for the nonelectrostatic anisotropic potential. The latter theory, which has also been applied by considering an atom-atom interaction model, yields results in overall agreement with experimental data. 相似文献
15.
A high resolution diode laser absorption spectrum of the ν 9 R Q 0 branch of C 2H 6 at 822 cm -1 reveals a rotational progression with anomalous spacing and intensity, which is shown to be a result of both l-doubling and torsional splitting of rotational levels, both of which give rise to a J( J+1) energy dependence. From a contour analysis of the spectrum we estimate values for the l-doubling and torsional splitting parameters. 相似文献
16.
This paper is concerned with an analysis of both 14NH 2D and 14ND 2H spectra obtained in the 730- to 1080-cm −1 region with a long-path Fourier transform spectrometer. The assignment of the observed transitions together with a theoretical analysis of the vibration-inversion-rotation energy levels concerned with these transitions allows the first determination of the spectroscopic constants related to the symmetric and antisymmetric upper levels of the fundamental ν2 band. 相似文献
17.
The combination band ν 5 + ν 12 of ethylene, C 2H 4, has been recorded for the first time with a high resolution Fourier transform spectrometer Bruker IFS 125HR. Assignments of transitions and preliminary rotational analysis are made. Two models (Hamiltonian of the isolated vibrational state and Hamiltonian that takes into account resonance interactions) are used. Influence of the local resonance interactions on the parameters and reproduction power of the models is discussed. 相似文献
18.
The strong infrared absorption in the ν 3 S–F stretching region of sulphur hexafluoride (SF 6) near 948 cm ?1 makes it a powerful greenhouse gas. Although its present concentration in the atmosphere is very low, it is increasing rapidly, due to industrial pollution. The ground state population of this heavy species is only 32% at room temperature and thus many hot bands are present. Consequently, a reliable remote-sensing spectroscopic detection and monitoring of this species require an accurate modelling of these hot bands. We used two experimental set-ups at the SOLEIL French synchrotron facility to record some difference and combination bands of SF 6: (1) a new cryogenic multiple pass cell with 93 m optical path length and regulated at 163 ± 2 K temperature and (2) the Jet-AILES supersonic expansion set-up. With this, we could obtain high-resolution absorption spectra of the ν 3 ? ν 1, ν 3 ? ν 2, ν 1 + ν 3 and ν 2 + ν 3 bands at low temperature. These spectra could be assigned and analysed, thanks to the SPVIEW and XTDS computer programs developed in Dijon. We performed two global fits of effective Hamiltonian parameters. The first one is a global fit of the ground state, ν 2, ν 3, ν 3 ? ν 2, ν 2 + ν 3, 2ν 3 and 2ν 3 ? ν 3 rovibrational parameters, using the present spectra and previous infrared, Raman and two-photon absorption data. This allows a consistent refinement of the effective Hamiltonian parameters for all the implied vibrational levels and a new simulation of the 2ν 3 + ν 2 ? ν 2 hot band. The second global fit involves the present ν 3 ? ν 1 and ν 1 + ν 3 lines, together with previous ν 1 Raman data, in order to obtain refined ν 1 parameters and also ν 1 + ν 3 parameters in a consistent way. This allows to simulate the ν 3 + ν 1 ? ν 1 hot band. 相似文献
19.
The parameters of NH 2D in the ground and ν2 states have been refined by a simultaneous analysis of the microwave, FTIR, and diode laser data. The intensities of 46 NH 2D lines have been measured, and from a least-squares fit of the intensity data the a ← s, s ← a, s ← s, and a ← a transition moments have been derived. The intensities of the lines in the ν2 band of NH 2D have been calculated taking into account the inversion-rotation interaction. The accuracies of the wavenumbers and intensities calculated with the new parameters are estimated to be better than ±0.0002 cm −1 and ±5%, respectively. The matrix elements for interaction of vibrations through x, y, and z axis couplings are appended. 相似文献
20.
High-spin levels of ^189Pt have been studied with the in-beam T-spectroscopy method via the ^176Yb(^18O,5n) reaction at the beam energies of 88 and 95 MeV. The previously known "vi-1 13/2 band has been confirmed, and its unfavored signature branch extended up to the 31/2^+ state. Within the framework of the triaxial particle-rotor model, the vi-1 13/2 band is suggested to be associated with the 11/2[615] configuration, and to have triaxial deformation. 相似文献
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