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X-ray absorption spectra: K-edges of 3d transition metals,L-edges of 3d and 4d metals,and M-edges of palladium 总被引:1,自引:0,他引:1
The X-ray absorption spectra of the 3d and 4d transition metals have been calculated within the single-particle approximation by a new linearized augmented plane wave method. The spectra, calculated with sharp atomic and band-structure single-particle levels, have been convoluted with a Lorentzian broadening function whose width is the sum of that of the core hole and the excited electrons. Plots are shown for (i) the K-edge fine structures up to at least 100 eV above the edge for Ca, Ti, Cr, Co, Cu, and Zn, (ii) the L2, 3 white lines for Ca, Ti, Cr, Co, and Cu, (iii) the L3 white lines for Sr, Zr, Nb, Ru, Rh, and Pd, and (iv) the M2, 3 and M4,5 spectrum of Pd. Systematic features which depend on the crystal structure and the placement of the Fermi level with conduction band are briefly discussed. 相似文献
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The general features of the geometries and electronic properties for 3d,4d,and 5d transition-metal atom doped Au 6 clusters are systematically investigated by using relativistic all-electron density functional theory in the generalized gradient approximation(GGA).A number of structural isomers are considered to search the lowest-energy structures of M@Au 6 clusters(M=3d,4d and 5d transition-metal atoms),and the transition metal atom locating in the centre of an Au 6 ring is found to be in the ground state for all the M@Au 6 clusters.All doped clusters,expect for Pd@Au 6,show large relative binding energies compared with a pure Au 7 cluster,indicating that doping by 3d,4d,5d transition-metal atoms could stabilize the Au 6 ring and promote the formation of a new binary alloy cluster. 相似文献
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用多组态自洽场方法,结合提出的半经验拟合公式,计算了高离化态类钴Rh^18 离子3p^63d^9—3p^53d^10,3p^63d^9—3p^63d^84p跃迁和振子强度,并与实验进行了比较. 相似文献
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L. Zem
o W. Drenckhahn A. Feigel E. Finckh K. Rüskamp P. Urbainsky M. Wangler 《Nuclear Physics A》1982,380(3):493-501
The yield of the 209Bi(d, γ)211g.s.Po and 211mPo (T1/2 = 25.2s) reaction was measured for deuteron energies Ed = 8–11.5 MeV. The reaction was identified by the -activities of the Po isotope. At Ed = 10.43 MeV, the (d, γ) cross section for the population of the ground state of 211Po is σg.s. = 16 ± 3 μb, the ratio relative to the cross section for the metastable state is σg.s./σm = 25.4 ± 0.9. These values and the yield curves were compared with calculations using a simple model for the population of the two states. In the excitation region E* = 15–19 MeV, the branching ratio of γ- to particle emission is nearly constant and has a value of about 0.4 × 10−4. 相似文献
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Jing-Shang ZHANG 《理论物理通讯》1991,16(4):439-442
The difference between two reaction cross sections of d(d, p)T and d(d, n)3He has been estimated in the cold fusion. It is caused by the different potential wall transmission and the angular distribution due to the structure.of deuterons. The rough estimation indicates that the branching ratio b about two orders of magnitude. 相似文献
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《Journal of Electron Spectroscopy and Related Phenomena》2002,127(3):139-152
Dissociative multiple photoionization of the bromine, the iodine monobromide, and the iodine molecules in the Br(3d,3p,3s) and I(4d,4p,4s,3d,3p) inner-shell regions has been studied by using time-of-flight (TOF) mass spectrometry coupled to synchrotron radiation in the ranges of 90∼978 eV for Br2, 60∼133 eV for IBr, and 86∼998 eV for I2. Total photoion and photoion–photoion coincidence (PIPICO) yields have been recorded as functions of the photon energy. Here, giant shape resonances have been observed beyond the thresholds of the inner-shells owing to the Br(3d10)→Br(3d9ϵf), I(4d10)→I(4d9ϵf), and I(3d10)→I(3d9ϵf) transitions. The dissociation processes of the multiply charged parent ions have also been evaluated from variations of photoelectron–photoion coincidence (PEPICO) and PIPICO spectra with the photon energy. From each Br(3p3/2) (189.9 eV) and I(4p3/2) threshold (129.9 eV), quintuple ionization of the molecules begins to play important roles in the photoionization, subsequently yielding ion pairs of X3+–X2+ (X=Br, I). From the I(3d5/2) threshold (627.3 eV), loss of six electrons from iodine molecule additionally begins to play a minor role in the multiple photoionization, giving rise to the formation of ion pairs of either I3+–I3+ or I4+–I2+. A direct comparison of the strengths and the ranges of the I(4d) and Br(3d) giant resonances was successfully made from dissociative photoionization of IBr. Over the entire energy range examined, 60<E<133 eV, biased charge spread relevant to the specific core-hole states of IBr is observed, presumably reflecting the fact that charge localizes mostly in the excited atoms, which can be accounted for mainly by a two step decay via a fast dissociation followed by autoionization upon the VUV absorption. 相似文献
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B. Jenny W. Grüebler V. König P.A. Schmelzbach R. Risler H.R. BürgI D.O. Boerma 《Nuclear Physics A》1979,324(1):99-108
Complete angular distributions of the differential cross section and all four deuteron-analyzing powers for 3He(d, d)3He scattering have been measured at 14 energies between 1.5 and 11.5 MeV. For all components the major changes in the observables occur below 7 MeV deuteron energy. 相似文献
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R. Cheikh J. Hanssen B. Joulakian 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,2(3):203-208
The fivefold differential cross section (5DCS) of the ionisation by electron impact of atomic sodium is determined theoretically
for its fundamental 3s(2
S) state and the excited 3p(2
P) and 3d(2
D) states by a procedure which employs in the transition matrix element of the first order Born approximation, the correlated
double continuum (3C) wave function. This permits us to determine the statistical M-state population and the orientation and alignment tensors in (e,2e) detection. It is also shown that, the use of Gamow correlation term, in the independent particle (2C) model, reproduces,
only in some situations, the shape of the angular distribution of the 5DCS obtained by the (3C) wave function.
Received: 17 November 1997 / Received in final form: 16 March 1998 / Accepted: 21 March 1998 相似文献
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H. Fischer Lehrstuhl Prof. R. Sizmann F. Bell 《Zeitschrift für Physik A Hadrons and Nuclei》1969,224(1-3):135-143
A selftarget of deuterium (0.5 atomic-% D) in a single copper crystal is produced by a 75 keV deuteron beam. The neutron yield from the D(d, n) 3He reaction shows a 30% increase compared with the yield in polycrystalline copper, if the crystal is oriented in 〈110〉 to the beam. This result is discussed in terms of the channelling behaviour of the penetrating deuterons parallel to the 110 lattice rows. 相似文献
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M. Hinczewski A. N. Berker 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(4):461-472
The anisotropic d=3 tJ model is studied by
renormalization-group theory, yielding the evolution of the system
as interplane coupling is varied from the isotropic
three-dimensional to quasi-two-dimensional regimes.
Finite-temperature phase diagrams, chemical potential shifts, and
in-plane and interplane kinetic energies and antiferromagnetic
correlations are calculated for the entire range of electron
densities. We find that the novel τ phase, seen in earlier
studies of the isotropic d=3 tJ model, persists even for
strong anisotropy. While the τ phase appears at low
temperatures at 30–35% hole doping away from 〈
ni〉=1, at smaller hole dopings we see a complex lamellar
structure of antiferromagnetic and disordered regions, with a
suppressed chemical potential shift, a possible marker of
incommensurate ordering in the form of microscopic stripes. An
investigation of the renormalization-group flows for the isotropic
two-dimensional tJ model also shows a clear pre-signature of the
τ phase, which in fact appears with finite transition
temperatures upon addition of the smallest interplane coupling. 相似文献
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Piedad Martin Jose Campos 《Journal of Quantitative Spectroscopy & Radiative Transfer》1978,19(1):109-111
Relative transition probabilities for twenty near-i.r. electric dipole lines and for three forbidden lines of Ne(I) with origin in the 3d′(5/2)2, 3d′(5/2)3 and 3d′(3/2)1 levels have been measured. The calculated lifetime in jK coupling of the 3d′(5/2)2 and 3d′(5/2)3 levels was used to put on an absolute scale the transition probabilities of fourteen lines. The values of the present work are compared with theoretical calculations obtained by use of the Coulomb approximation and the intermediate-coupling scheme. 相似文献
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用多组态自洽场方法,结合我们提出的半经验拟合公式,计算了高离化态类钴Pd19+离子3p63d9-3p53d10,3p63d9-3p83d84p跃迁和振子强度,并与实验符合得较好。 相似文献