共查询到20条相似文献,搜索用时 36 毫秒
1.
O. Aspelund D. Ingham A. Djaloeis H. Kelleter C. Mayer-Bricke 《Physics letters. [Part B]》1974,50(4):441-444
Angular distribution of the reaction 12C(d,τ) 11B leading to the 3/2− ground state and the 4.44 MeV excited (5/2− state 11B have measured at Ed = 80 MeV up to about 70° and 40°, respectively. The inclusion of second-order processes in the framework of CCBA calculations gives a good reproduction of the 3/2− as well as of the DWBA forbidden 3/2− angular distribution. The strong dependence of the cross section on the sign of the deformation supports a positive β2 value for 11B. 相似文献
2.
A C.W. multi-mode dye laser is used to obtain by optical pumping an orientation of the 2p5 3s3P0 (F = 3/2) state of 21Ne. A magnetic resonance experiment leads to the measurement of the g factor g (3P0) = 3.027 (8) × 10−4 to be compared with the theoretical prediction (3.025(6) × 10−4). One obtains also the metastability exchange cross section σ(3P0) = 18.4 ± 4 Å2 for collisions between metastable (3P0) Ne atoms and ground state Ne atoms. This result is compared with other measurements and theoretical evaluation. 相似文献
3.
D. K. Olsen A. R. Barnett S. F. Biagi N. H. Merrill W. R. Phillips 《Nuclear Physics A》1974,220(3):541-568
The static quadrupole moments of the first excited Jπ = 2+ states in 20Ne and 22Ne and the reduced electric quadrupole transition probabilities of these states to the ground states were measured via projectile Coulomb excitation. The quadrupole moments were deduced from the shapes of γ-ray angular distributions. The results are: Q(20Ne, 2+) = −0.20±0.05 b and Q(22Ne, 2+) = −0.11±0.05 b. The transition strengths were deduced from yield measurements and by comparison with the yields of target γ-rays. The results are: B(E2; 0+ → 2+, 20Ne) = 0.037±0.003 e2 · b2 and B(E2; 0+ → 2+, 22Ne) = 0.025±0.002 e2· b2. The results for the transition strengths are consistent with the results of accurate timing methods and resolve discrepancies between previous experiments. The results for the quadrupole moments are consistent with earlier measurements, although the mean values we obtain are slightly lower. The experimental measurements are compared with theoretical predictions and a detailed discussion is given of corrections to this type of reorientation experiment. 相似文献
4.
G. B. Vingiani C. Rossi-Alvarez A. Buscemi F. Brandolini
F. Cervellera
《Physics letters. [Part B]》1972,40(6):638-640The g-factor of the 3/2− state at 153 keV in 49V was measured with the 48Ti(p, γ)49V reaction and the differential spin-precession method. The g value and the remeasured mean life are g = 1.58 ± 0.08 and τ = 28.7 ± 0.5 ns. The result is compared with some theoretical predictions. 相似文献
5.
From the temperature dependence of the line—band luminescence intensity ratio of LiBaF3:Eu2+ a 4f−5d activation energy (Δ) of 800 cm−1 is derived, being much higher than the value reported in the literature (100 cm−1). The temperature dependence of the luminescence decay can be well described with Δ = 800 cm−1 and with 4f−4f and 5d−4f radiative probabilities of 4×102s−1 and 6×105s−1, respectively. 相似文献
6.
J. Bernabu 《Physics letters. [Part B]》1979,80(4-5):396-400
Parity violating effects due to neutral currents in isoscalar 0+→1+ nuclear transitions induced by electron scattering are enhanced owing to the small isoscalar magnetic dipole strength. A polarization asymmetry of the order 10−4 is expected at q 100 MeV for the 12C transition to the 1+(T = 0) state at 12.71 MeV. It would allow to single out the (electron vector current) × (hardonic axial isoscalar current) quantum numbers and couplings of the neutral current interaction. 相似文献
7.
C. W. De Jager P. H. M. Keizer E. A. J. M. Offermann H. De Vries 《Physics letters. [Part B]》1985,150(6):421-424
Electroexcitation of the first excited state in 39K has been studied in the momentum transfer region of 0.8–2.5 fm−1. Separation of the longitudinal and transverse form-factor components has been obtained. The longitudinal form factor has been analyzed model-independently. A B (M1) value for this l-forbidden transition was also obtained. Presently available theoretical predictions are unable to reproduce the B(M1) value or the transverse form-factor data. 相似文献
8.
J. J. Davies 《Physics letters. A》1972,40(5):423-424
Using ENDOR, the hyperfine constant of 53Cr+ in KMgF3 is found to be 53A = (20.754 ± 0.003) × 10−4cm−1. Taken with recent data for Cr+ in other environments, the result confirms that the dependence of 53A on covalency is remarkably linear. 相似文献
9.
Yu-Ju Shin Mi-Hyae Park Ji-Hyeon Kwak Hyun Namgoong Oc Hee Han 《Solid State Ionics》2002,150(3-4):363-372
Layer-type oxide NaxMx/2IITi1−x/2IVO2 (M=Co, Ni; 0.60≤x≤1.0) has been prepared by solid state reactions. In both series, two structural variants of type -NaFeO2 (O3) and β-RbScO2 (P2) have been obtained consecutively as x decreases with a borderline composition around xc0.7. With the decrease of x, the ionic conductivity has been found to increase up to 8.4×10−2 S cm−1 at 770 K (Na0.67Co0.33Ti0.67O2). Compositions of P2 have been found to exhibit the conductivity values two to five times greater than those of O3, primarily due to the larger rectangular threshold available for the diffusion of Na+ ions. Such a structural effect has also been considered to depend on the polarizability of alkali ion. HT-XRD and 23Na-NMR data of Na0.67Co0.33Ti0.67O2 strongly suggest that the diffusion of Na+ ion is deeply related with the local distortion of trigonal prismatic sites, leading to the change of activation energy around 430 K. 相似文献
10.
D. H. Gloeckner M. H. MacFarlane
R. D. Lawson
F. J. D. Serduke 《Physics letters. [Part B]》1972,40(6):597-601Measured E2 transition rates in the N = 50 isotones (90Zr–94Ru) are satisfactorily reproduced by a shell model 0699 0 with proton configurations (p1/2g9/2)n. The inhibited 8+→6+ E2 transition in 94Ru and its connection with seniority mixing is discussed. Isomeric
states are predicted in 91Nb and 93Tc. 0699 相似文献
11.
J. W. Tape N. Benczer-Koller R. Hensler
J. R. MacDonald
《Physics letters. [Part B]》1972,40(6):635-637The mean life of the 3.74 MeV (3−) excited state of 40Ca has been directly measured by a particle-gamma delayed coincidence technique. A mean life τ = 59 ± 5 ps was obtained, corresponding to a transition strength B(E3) = 31 ± 3 W.u. 相似文献
12.
S. Svensson L. Karlsson N. M rtensson P. Baltzer B. Wannberg 《Journal of Electron Spectroscopy and Related Phenomena》1990,50(2):C1-C7
The energy of the 1s2s22p62S) core excited state in atomic fluorine is determined by studying a satellite in the electron beam excited KVV Auger electron spectrum of HF. The satellite is assigned to an atomic autoionization transition 1s2(22p6(2S) → 1ss22p4 (1D). The energy of the 1s2s22P6(2s) initial state has been determined to be 676.5 eV. Transitions to the 1s22s22p43p(3P)and 1s22s22P4(1S) states are also observed. The intensity for these transitions is very low. 相似文献
13.
Jun Wang Yaxun Zhou Shixun Dai Tiefeng Xu Qiuhua Nie 《Physica B: Condensed Matter》2007,400(1-2):224-228
The spectroscopic properties of Er3+/Yb3+ co-doped Bi2O3–B2O3–WO3 (BBW) glasses were analyzed and discussed. The effect of WO3 content on the absorption spectra, the Judd–Ofelt parameters Ωt (t=2, 4, 6), emission spectra and the lifetime of the 4I13/2 level and the quantum efficiency of Er3+:4I13/2→4I15/2 transition were also investigated. With the substitution of WO3 for B2O3, the measured lifetime of the 4I13/2 level and the quantum efficiency of Er3+:4I13/2→4I15/2 transition increase from 0.98 to 1.31 ms and from 38.2% to 49.2%, respectively. The effective width of emission band and the emission cross-section both decrease slightly. And the emission spectra is analyzed via the different curve (σe−σa) of BBW glasses, the influence of OH−is also discussed. 相似文献
14.
Anthony V. Powell Rachel J.E. Lees Ann M. Chippindale 《Journal of Physics and Chemistry of Solids》2008,69(4):1000-1006
The chromium(II) antimony(III) sulphide, [Cr((NH2CH2CH2)3N)]Sb4S7, was synthesised under solvothermal conditions from the reaction of Sb2S3, Cr and S dissolved in tris(2-aminoethyl)amine (tren) at 438 K. The products were characterised by single-crystal X-ray diffraction, elemental analysis, SQUID magnetometry and diffuse reflectance spectroscopy. The compound crystallises in the monoclinic space group P21/n with a=7.9756(7), b=10.5191(9), c=25.880(2) Å and β=90.864(5)°. Alternating SbS33− trigonal pyramids and Sb3S63− semi-cubes generate Sb4S72− chains which are directly bonded to Cr(tren)2+ pendant units. The effective magnetic moment of 4.94(6)μB shows a negligible orbital contribution, in agreement with expectations for Cr(II):d4 in a 5A ground state. The measured band gap of 2.14(3) eV is consistent with a correlation between optical band gap and framework density that is established from analysis of a wide range of antimony sulphides. 相似文献
15.
P. Federman 《Physics letters. [Part B]》1984,140(5-6):269-271
The constancy in excitation energy of the lowest 2+ state in the Sr isotopes across sthe N=56 subshell closure is shown to result from a reduction in the 2p1/2−2p3/2 proton spin-orbit splitting as the 2d5/2 neutron orbital is filled 相似文献
16.
V Werner D Belic P von Brentano C Fransen A Gade H von Garrel J Jolie U Kneissl C Kohstall A Linnemann A.F Lisetskiy N Pietralla H.H Pitz M Scheck K.-H Speidel F Stedile S.W Yates 《Physics letters. [Part B]》2002,550(3-4):140-146
Following the successful identification of mixed-symmetric one- and two-phonon states in the N=52 nuclei 94Mo and 96Ru, we have performed a photon scattering experiment on the N=52 isotone 92Zr. Experimental data and shell model calculations show that both, single particle and collective degrees of freedom are present in the low-lying levels of 92Zr. The second excited quadrupole state shows the signatures of the one-phonon mixed-symmetric 2+ state, while calculations and data indicate an almost pure neutron configuration for the 2+1 state, in contradiction with the F-spin symmetric limit. Furthermore, two strong dipole excitations, which are candidates for the two-phonon quadrupole–octupole coupled E1 excitation and for the mixed-symmetric 1+ two-phonon state, were observed. 相似文献
17.
Partha Guha 《Journal of Geometry and Physics》2003,46(3-4):231-242
It is known that the Korteweg–de Vries (KdV) equation is a geodesic flow of an L2 metric on the Bott–Virasoro group. This can also be interpreted as a flow on the space of projective connections on S1. The space of differential operators Δ(n)=∂n+u2∂n−2++un form the space of extended or generalized projective connections. If a projective connection is factorizable Δ(n)=(∂−((n+1)/2−1)p1)(∂+(n−1)/2pn) with respect to quasi primary fields pi’s, then these fields satisfy ∑i=1n((n+1)/2−i)pi=0. In this paper we discuss the factorization of projective connection in terms of affine connections. It is shown that the Burgers equation and derivative non-linear Schrödinger (DNLS) equation or the Kaup–Newell equation is the Euler–Arnold flow on the space of affine connections. 相似文献
18.
Hongwei Song Jiahua Zhang Diankun Gao Shihua Huang Jiaqi Yu 《Optics Communications》1995,120(5-6):264-268
We report the changes of the 5DJ-7F0(J = 2, 1, 0) transition probability with composition y and its effect on the hole burning quantum efficiency in the SryBa1−yFCl0.5Br0.5:Sm2+ system. We observed that the 5DJ-7F0 transition probability increases with the increase of Sr concentration. This result is attributed to the reduction of the energy separation between the 5DJ level and the 4f5d bands, which makes the electron wave functions of 5DJ states mix further with that of the 4f5d states. The dependence of the hole-burning quantum efficiency on the 5DJ-7F0 transition probability was derived by the dynamical equations of the spectral hole burning of divalent samarium. Furthermore, the hole-burning experiments in SrFCl0.5Br0.5:Sm2+ and BaFCl0.5:Sm2+ were performed under the same conditions. The experimental results present that the hole-burning quantum efficiency of SrFCl0.5Br0.5:Sm2+ is higher than that of BaFCl0.5Br0.5:Sm2+. 相似文献
19.
M. Metcalf G. Neuhofer F. Niebergall M. Regler H. Stier K. Winter
J. J. Aubert
X. De Bouard V. Lepeltier L. Massonnet H. Pessard M. Vivargent T. R. Willitts M. YvertW. Bartl
M. Steuer 《Physics letters. [Part B]》1972,40(6):703-707The time-dependence of the decay rate of initially pure K0 into the final state (π+π−π0) has been studied in search for the decay kS0→π+π−π0. No evidence is found in a sample of 384 observed events. The ratio of the CP -violating KS0 amplitude and the KL0 amplitude is η+−0 = (0.13−0.20+0.17) + i(0.17−0.26+0.27); the ratio of the CP-conserving KS0 amplitude and the KL0 amplitude is < 0.4. The energy dependence of the K0→π+π−π0 matrix element is found to be a+−0 = −0.31 ± 0.03. 相似文献
20.
The 59.5 keV Mössbauer resonance of 237Np has been measured in Np3S5 at 77 and 4.2 K. At 77 K, two different quadrupolar splittings are observed. The first one (δ1 = −5(1) mm sec−1/NpAl2) is assigned to the Np4+ ions and the second one (δ2 = 28(1) mm sec−1/NpAl2) is assigned to the Np3+ ions. At 4.2 K the spectrum gives a ratio of areas S(Np3+)/S(Np4+) of 2.0. These results clearly confirm the crystallographic data of this mixed-valence material. 相似文献