共查询到10条相似文献,搜索用时 125 毫秒
1.
T. Bäck B. Cederwall R. Wyss A. Johnson J. Cederkäll M. Devlin J. Elson D.R. LaFosse F. Lerma D.G. Sarantites R.M. Clark P. Fallon I.Y. Lee A.O. Macchiavelli R.W. Macleod 《The European Physical Journal A - Hadrons and Nuclei》1999,6(4):391-397
High-spin states in 88Mo were studied using the Gammasphere germanium detector array in conjunction with the Microball CsI(Tl) charged-particle
detector system. Three γ-ray cascades with dynamic moments of inertia showing similar characteristics to superdeformed rotational
bands observed in the neighbouring A= 80 region have been identified and assigned to the nucleus 88Mo. The quadrupole moment of the strongest band, deduced by the Residual Doppler Shift Method, corresponds to a quadrupole
deformation of β2≈ 0.6. This confirms the superdeformed nature of this band. The experimental data are interpreted in the framework of total
routhian surface calculations. All three bands are assigned to two-quasi-particle proton configurations at superdeformed shape.
Received: 20 May 1999 / Revised version: 25 August 1999 相似文献
2.
G. Schönwaßer H. Hübel G.B. Hagemann J. Domscheit A. Görgen B. Herskind G. Sletten J.N. Wilson D.R. Napoli C. Rossi-Alvarez D. Bazzacco R. Bengtsson H. Ryde P.O. Tjøm S.W. Ødegård 《The European Physical Journal A - Hadrons and Nuclei》2002,13(3):291-296
Lifetimes of states in the yrast superdeformed bands of 163Lu and 164Lu were determined in a Doppler-shift attenuation-method experiment. From fractional Doppler shifts and line shapes, average
transition quadrupole moments, Q
t = 8.2-0.6
+1.0 b and 7.1-0.6
+0.5 b, were deduced for one of the bands in 163Lu and 164Lu, respectively. These values are much larger than the quadrupole moment of the normal-deformed yrast band in 163Yb, Q
t = 4.9-0.4
+1.3 b, that was also determined in this experiment. Comparison to cranking calculations indicates that both superdeformed bands
correspond to a local potential energy minimum with a pronounced triaxiality, γ∼ 20°.
Received: 8 November 2001 / Accepted: 9 January 2002 相似文献
3.
H. Röpke J. Brenneisen M. Lickert 《The European Physical Journal A - Hadrons and Nuclei》2002,14(2):159-167
Eight high-spin states in 36Ar below 10MeV excitation energy, among them a prospective J
π = 8- state at 9408keV and the J? 8 levels of the recently discovered superdeformed rotational band, have been observed by n-γ coincidence measurements with
the 33S(α, nγ) reaction at E
α = 14.4 and 13.4MeV. High-spin assignments of, respectively, J
π = 6+ and 5- were obtained for the E
p = 1209 and 1462keV (E
x = 9682 and 9927keV) resonances of the 35Cl (p,γ) reaction by a measurement of γ-ray angular distributions. The spectrum of the high-spin and of the E
x? 7.4MeV levels is decomposed according to the underlying shell model configurations with n = 0, 1, 2, 4 particles excited from the N = 2 into the N = 3 major shell. The role of four-particle excitations, all connected with large prolate distortions, is elucidated for the
entire A = 36-40 mass region.
Received: 21 December 2001 / Accepted: 25 March 2002 相似文献
4.
R.B. López-Martens T.W. Schmidt G. Roberts 《Applied physics. B, Lasers and optics》2002,74(6):577-581
The cycle-averaged ac Stark effect associated with the [
A
]2Σ+v′=2?[
X
]2Π1/2v′=0 two-photon absorption of NO at intensities between 7.7 and 15.2 TW cm-2 has been characterized in real time through a synergic combination of bichromatic laser experiments and quantum-dynamics
calculations. Measurements of the fluorescence emitted by the Rydberg [
A
]2Σ+v′=2 level as a function of time between Stark and probe components of a bichromatic field exhibit a characteristic evolution
in temporal peak structure with Stark-field intensity, which is interpreted in terms of a time-dependent Floquet analysis
of the laser–matter interaction. The experimental observations are consistent with a dynamic Stark shift of Δεs(ω1,ω2)≤0.23 eV of the optical transition at these intensities.
Received: 18 January 2002 / Revised version: 6 March 2002 / Published online: 24 April 2002 相似文献
5.
R. Loritz O. Iordanov E. Galindo A. Jungclaus D. Kast K.P. Lieb C. Teich F. Cristancho Ch. Ender T. Härtlein F. Köck D. Schwalm 《The European Physical Journal A - Hadrons and Nuclei》1999,6(3):257-268
Subpicosecond lifetimes of high spin states in the rotational nuclei 73Se, 74Se and 74Br have been measured using the 58Ni +19F compound reaction and the Doppler Shift Attenuation method. Six EUROBALL Cluster detectors arranged in cube geometry allowed
us to select the relevant transitions in γγ coincidence mode. The high counting statistics achieved in this setup also facilitated
the determination of average sidefeeding times, which were found to agree rather well with the results of Monte-Carlo calculations
of the particle and γ-ray evaporation process. The deduced quadrupole strengths and deformations are compared with the results
of previous measurements and the predictions of Cranked Shell Model calculations. In 74Br, a large and constant prolate deformation of β2= 0.37(1) was found for the presumed 4+ and 3− two-quasiparticle bands.
Received: 2 July 1999 相似文献
6.
W. Urban J.A. Pinston T. Rzaca-Urban A. Złomaniec G. Simpson J.L. Durell W.R. Phillips A.G. Smith B.J. Varley I. Ahmad N. Schulz 《The European Physical Journal A - Hadrons and Nuclei》2003,16(1):11-15
A new band, populated by the spontaneous fission of 248Cm and studied by means of prompt γ-ray spectroscopy using the EUROGAM2 array, was observed in 99Zr. The 1038.8 keV band head with a half-life T
1/2 = 54(10) ns is interpreted as a K-isomer, corresponding to the 9/2[404] neutron-hole excitation. It is the first observation of this orbital in the mass A ∼ 100 region. The quadrupole moment, Q
0 = 3.9(3) eb deduced for the new band indicates a large deformation of β = 0.41, which is produced by a specific shape-coexistence
mechanism, known in other regions and now found in the A ∼ 100 nuclei.
Received: 11 September 2002 / Accepted: 31 October 2002 / Published online: 17 January 2003
RID="a"
ID="a"e-mail: urban@fuw.edu.pl
Communicated by D. Schwalm 相似文献
7.
Current-voltage (J-V) and differential-conductivity-voltage ( dJ/dV-V) characteristics are analytically calculated at zero temperature for a point contact consisting of: two Peierls conductors
P
( = 1, 2) separated by an insulator (I). Here P is a conductor with charge density wave (CDW). The J-V and dJ/dV-V characteristics depend on the CDW phases ( = 1, 2) in the mean field approximation. To calculate them analytically we assumed, = ≡Δ where ( = 1, 2) are the energy gaps of P
( = 1, 2). The current J has a discontinuous jump at eV = 2Δ for ϕ
1 = ϕ
2≠ 0. The differential conductivity dJ/dV has a singularity at eV = 2Δ for ϕ
1 = ϕ
2≠ 0. The relation J(V,ϕ
1,ϕ
2) = - J(- V,ϕ
1 + π,ϕ
2 + π) is obtained.
Received 4 July 2001 and Received in final form 13 September 2001 相似文献
8.
B. Bodermann H. Knöckel E. Tiemann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2002,19(1):31-44
Based on new systematic high precision measurements of hyperfine splittings in different rovibrational bands of 127I2 in the near infrared spectral range between 778 nm and 816 nm, and the data in the range from 660 nm to 514 nm available
from literature, the quantum number dependence of the different hyperfine interaction parameters was reinvestigated. As detailed
as possible parameters were re-fitted from the reported hyperfine splittings in literature, considering that the interaction
parameters should vary smoothly with the vibrational and rotational quantum numbers, and follow appropriate physical models.
This type of consistency has not been sufficiently taken into account by other authors. To our knowledge it is now possible
for the first time to separate the hfs contributions of the two electronic states B
3
and X
1
Σ
+
g
for optical transitions in a very large wavelength range. New interpolation formulae could be derived for both states, describing
the quantum number dependences of the nuclear electric quadrupole, of the nuclear spin-rotation and also of the nuclear spin-spin
interactions. Using these new interpolation formulae the hyperfine splittings for the components with the quantum number condition
F
-
J
= 0 can be calculated with an uncertainty of ≤30 kHz for transitions in the wavelength range between 514 nm and 820 nm.
Received 17 July 2001 and Received in final form 17 October 2001 相似文献
9.
D. Schwarzhans D. Zimmermann 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(2):193-198
The absorption spectrum of NaAr has been investigated with high resolution using a supersonic beam of molecules and a tunable
dye laser. About 3 300 absorption lines due to the transition A
2
Π ←
X and B
2
Σ ←
X have been observed. In addition, we observed the spectral distribution of the fluorescence for a particular absorption line.
From all experimental data the X
2
Σ
+
interaction potential has been deduced in a fully quantum-mechanical method of approach. The potential is given in terms
of an analytical Hartree-Fock-Dispersion function. For the equilibrium parameters of the X state we get R
e
= 5.01(1) ? and D
e
= 41.6(2)
cm
-1
.
Received 28 August 2002 / Received in final form 15 October 2002 Published online 17 December 2002
RID="a"
ID="a"Now at Knick Elektronische Messger?te, Beuckestr. 22, 14163 Berlin, Germany.
RID="b"
ID="b"e-mail: dz@kalium.physik.tu-berlin.de 相似文献
10.
K.-M. Källman M. Brenner V.Z. Goldberg T. Lönnroth P. Manngård A.E. Pakhomov V.V. Pankratov 《The European Physical Journal A - Hadrons and Nuclei》2003,16(2):159-169
The excitation function and angular distributions of elastic α-particle scattering on 28Si have been measured in the laboratory energy range 6-28 MeV using a backscattering technique on a thick target, yielding
a continuous energy distribution. More than 200 narrow states are observed, with widths in the range ∼ 30-100 keV at excitation
energies E
* = 13-32 MeV. Angular distributions at backward angles were measured, and angular momentum values of more than 83 states have
been deduced. The analysis gives spin-parities J
π, α-partial widths Γα and reduced widths of the narrow high-lying resonant states in 32S. The experimentally observed states display both the negative- and the positive-parity rotational-like sequences with seemingly
no parity splitting, a finding which is at variance with most potential-model predictions. The deduced effective moment of
inertia indicates a more extended structure than the ground-state configuration. The observed strength of each ℓ-value is
analyzed in terms of an underlying split doorway state of Lorentzian form, which yields an interpretation as fragmented rotational
α + 28Si states.
Received: 26 June 2000 / Accepted: 16 September 2002 / Published online: 4 February 2003
RID="a"
ID="a"e-mail: kkallman@abo.fi
RID="b"
ID="b"Present address: Swedish Polytechnic, FIN-65200 Vasa, Finland.
Communicated by D. Guerreau 相似文献