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1.
2.
A.P. Hitchcock C.E. Brion 《Journal of Electron Spectroscopy and Related Phenomena》1978,13(3):193-218
Small angle inelastic scattering of 2.5 keV electrons was used to study inner shell excitation in the methyl halides at energy transfers between 50 and 700 eV. Discrete peaks due to the excitation of carbon K, fluorine K, chlorine L, bromine M4, 5 and iodine N 4, 5 electrons were observed. Correlations through the methyl halide series were used to aid in the assignment of features in the carbon K-shell spectra. A comparison of halogen inner-shell excitation structures with the carbon K-shell excitation structure in the same molecule allowed a complete assignment of all spectral features. The assignments proposed involve promotions of inner shell electrons to unoccupied valence and Rydberg orbitals. On the basis of our assignments of the chlorine L- and carbon K-shell electron energy loss spectra of CH 3Cl we propose an alternate assignment of the previously reported CH 3Cl chlorine K-shell photoabsorption spectrum. 相似文献
3.
Investigation of the multiplet features of SrTiO3 in X‐ray absorption spectra based on configuration interaction calculations 下载免费PDF全文
M. Wu Houlin L. Xin J. O. Wang X. J. Li X. B. Yuan H. Zeng J.-C. Zheng H.-Q. Wang 《Journal of synchrotron radiation》2018,25(3):777-784
Synchrotron‐based L2,3‐edge absorption spectra show strong sensitivities to the local electronic structure and chemical environment. However, detailed physical information cannot be extracted easily without computational aids. Here, using the experimental Ti L2,3‐edges absorption spectrum of SrTiO3 as a fingerprint and considering full multiplet effects, calculations yield different energy parameters characterizing local ground state properties. The peak splitting and intensity ratios of the L3 and L2 set of peaks are carefully analyzed quantitatively, giving rise to a small hybridization energy around 1.2 eV, and the different hybridization energy values reported in the literature are further addressed. Finally, absorption spectra with different linearly polarized photons under various tetragonal crystal fields are investigated, revealing a non‐linear orbital–lattice interaction, and a theoretical guidance for material engineering of SrTiO3‐based thin films and heterostructures is offered. Detailed analysis of spectrum shifts with different tetragonal crystal fields suggests that the eg crystal field splitting is a necessary parameter for a thorough analysis of the spectra, even though it is not relevant for the ground state properties. 相似文献
4.
X-Ray Magnetic Circular Dichroism experiments have been conducted on a vanadium inorganic salt and a vanadium enamino-ketone complex. Measurements at the K edge of oxygen and nitrogen reveal the amount of magnetic moment transferred in the 2p orbitals of the ligand atoms from the magnetic V ion. Measurements at the L edge of vanadium show that the orbital moment is small and that J = L + S, contrary to the expected J = L-S coupling for a 3d metal with less than five d-electrons. This surprising inobservance of Hunds third rule emphasizes the need for more detailed studies and calculations on such hybrid molecules.Received: 19 November 2003, Published online: 20 April 2004PACS:
75.20.-g Diamagnetism, paramagnetism, and superparamagnetism - 75.70.Ak Magnetic properties of monolayers and thin films - 78.70.Dm X-ray absorption spectra 相似文献
5.
L-shell photoelectric cross sections have been measured at 60 keV for six elements in the range 74≤Z≤92. The measurements are found to agree with theoretical calculations. 相似文献
6.
L-shell photoelectric cross-sections have been measured at 6 keV for eight elements in the range 40⩽Z⩽53. The measurements
agree with theoretical calculations. 相似文献
7.
G. Schütz M. Knülle R. Wienke W. Wilhelm W. Wagner P. Kienle R. Frahm 《Zeitschrift für Physik B Condensed Matter》1988,73(1):67-75
The spin-dependent absorption of circularly polarized x-rays is studied at theL-edges of ferromagnetic Gd and Tb metal. At theL
1-edge a spin-dependent part of the absorption coefficient of 10–3–10–2 is observed. Strong resonance absorption known as white line occurs at theL
2- andL
3-absorption onset. Correlated with it one finds large spin-dependent absorption effects with amplitudes of a few percent. The spin-dependent absorption spectra reflect the profiles of the spin densities of the states populated in the absorption process. Thep-states show spin densities correlated with the first two flat bands above the Fermi level. The spin density of thed-like states is concentrated in the energy range of the white line. In Gd a splitting of (0.5–0.6) eV of the unoccupied 5d spin up and spin down bands is indicated for both spin-orbit partners. In Tb a large dependence of the 5d spin density on the spin-orbit configuration is observed. The experimental results on the spin densities in Gd are compared with band structure calculations for the ferromagnetic ground-state. The theoretical and experimental spin density profiles agree well for thep-states but not for thed-states. The discrepancy concerning thed-states may be attributed to core-hole polarization effects in the absorption process. 相似文献
8.
G. Schütz R. Wienke W. Wilhelm W. Wagner P. Kienle R. Zeller R. Frahm 《Zeitschrift für Physik B Condensed Matter》1989,75(4):495-500
Large spin-dependent absorption effects have been observed with circularly polarized photons of energies between 10.8 keV and 13.8 keV at theL
2,3-edges of Os, Ir, Pt, and Au impurities (3 at.%) in iron. The largest value of the spin-dependent absorption coefficient (µ
c
/µ
o
+0.22) is found at the PtL
2-edge. From the energy dependence of the spin-dependent absorption at theL
2- andL
3-edges the spin-density profiles of thed
3/2-andd
5/2-projected states populated in the absorption process are derived. Thed
5/2-spin densities deduced from theL
3 spin-dependent absorption spectra agree well with spin-polarized band-structure calculations for the ferromagnetic ground state. A comparison of thed
3/2- andd
5/2-spin densities shows a strong contribution of the spin-orbit effects to the exchange splitting in Os, whereas only small spin-orbit effects are indicated for Ir, Pt and Au impurities. 相似文献
9.
Krishnamurthy V. V. Suzuki M. Kawamura N. Ishikawa T. Kohori Y. 《Hyperfine Interactions》2001,136(3-8):361-365
The formation of an induced 5d magnetic moment on Ir in Fe97Ir3, Co95Ir5 and Ni95Ir5 alloys has been investigated by X-ray magnetic circular dichroism (XMCD) and X-ray absorption spectra (XAS) measurements
at Ir L
2,3 edges. Using a sum rule which relates the integrals of these spectra with the ground state expectation value of the orbital
angular momentum 〈L
Z
〉 of the probed atom, the orbital moment m
orb of Ir could be determined as −0.071(2) μ
B
in an Fe host, −0.067(2) μ
B
in a Co host and −0.041(1) μ
B
in a Ni host. The spin magnetic moment m
spin of Ir is also found to be the maximal in Fe and the minimal in Ni. The total moment of Ir is found to be approximately 1/5
of total moment of Fe, 2/13 of the total moment of Co, and 1/4 of the total moment of Ni.
This revised version was published online in September 2006 with corrections to the Cover Date. 相似文献
10.
M. Sancrotti F. Ciccacci M. Finazzi E. Vescovo S. F. Alvarado 《Zeitschrift für Physik B Condensed Matter》1991,84(2):243-246
The unoccupied electronic structure of an opend-shell transition metal oxide, namely Fe3O4, has been addressed by measuring ultraviolet angle-integrated inverse photoemission (IP) spectra acquired in the isochromat mode (hv=10.2-24 eV). Exploitation of photon energy dependence of symmetry-projected IP cross-sections and comparison with the O 1s X-ray absorption spectrum allow us to recognize a strong covalent admixture of Fe [3d; 4 (sp)]-and O (2p)-derived states in this compound. 相似文献
11.
Summary Soft-X-ray generation in aluminium plasmas produced by Nd nano-second laser pulses is investigated analysing time-resolved
spectra ofK-shell line emission. Time histories of line emission and electron temperature as well as the time-integrated X-ray yield
were studied as a function of laser pulse duration and target position along the laser beam propagation axis. The experimental
results suggest that X-ray emission is influenced by self-focusing of laser light in the plasma.
Presently at Laboratoire pour l'Utilisations des Lasers Intenses, Ecole Polytechnique, 91128 Palaiseau Cedex, France. 相似文献
12.
研究了高电荷态离子129Xeq+(q=25,26,27)入射金属Mo表面产生的特征X射线谱.实验结果表明,在束流强度小于120nA条件下,高电荷态离子129Xeq+可以激发Mo的L壳层特征X射线谱.单离子X射线相对产额可达10-8量级,特征X射线的相对产额随入射离子的动能和电荷态(势能)的增加而增加.通过Mo原子的Lα1特征X射线谱,利用Heisenberg不确定关系对Mo原子的第M能级寿命进行了估算. 相似文献
13.
L. D. Finkel’shteĭn I. A. Nekrasov A. V. Lukoyanov É. Z. Kurmaev V. I. Anisimov S. Kučas A. Kynienė A. Moewes J. -L. Wang Z. Zeng 《Physics of the Solid State》2006,48(3):420-426
A strong elastic line has been found in the L 3 x-ray emission spectrum of metallic Mn. To unravel its physical nature, the ground-state properties of α-Mn were studied in comparison with those of 3d metals (Cr and Fe in bcc structure), as well as the properties of the L 3 absorption final states of these three transition metals. To model the electronic structure, LSDA band-structure calculations of Cr, Mn, and Fe were carried out, and L 3 absorption spectra of these metals were computed in the atomic approximation. A joint analysis of the properties of the ground state and of the final absorption state excited by an x-ray-produced core hole suggests that the elastic line in the α-Mn spectra should be assigned to the specific character of the absorption final-state multiplet. 相似文献
14.
R G Kulkarni 《Pramana》1980,14(6):455-461
TheL-shell internal excitation accompanyingL-capture has been treated relativistically by the use of hydrogenic wave functions. Numerical calculations for the nuclides37Ar,55Fe,77Ge,131Cs,157Tb,165Er,179Ta and193Pt have been performed for the first-time. The present calculations show that doubleL
i-hole production probability decreases with increasing atomic number and it is almost independent of transition energy for
a particular shell. Possible experiments to detect this phenomenon in atoms for whichK-K processes are energetically forbidden are discussed briefly. 相似文献
15.
D.V. Rao R. Cesareo G.E. Gigante 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(1):45-53
Elastic scattering cross-sections for Pd, Ag, Cd, In, Sn, Sb, Pt, Au and Pb are measured at an angle of 90 in the X-ray region 5.41 keV. These energies fall between the high-energy side of the L- and M-shell absorption edges of the atoms considered. The present atomic region is significant for solid X-rays to assess the contribution
of resonance and solid-state environmental effects. Also it is the anomalous scattering region for many of the atoms of the
periodic table. Experimental results are compared with theoretical calculations based on form factor formalisms including
the anomalous corrections and available recent S-matrix values. Based on the experimental evidence, the present results indicate the influence of solid-state environmental
effects, the importance of anomalous corrections nearer to absorption edges, the correctness of revised high-energy limit
values, the superiority of S-matrix predictions over form factor values on measured elastic scattering cross-sections in the X-ray regime and also show
the resonance behavior around K, L and M absorption edges.
Received: 27 January 1998 / Received in final form: 4 January 1999 相似文献
16.
Faisal Zeeshan Joanna Hoszowska Jean-Claude Dousse Dimosthenis Sokaras Tsu-Chien Weng Roberto Alonso-Mori Matjaz Kavčič Mauro Guerra Jorge Miguel Sampaio Fernando Parente Paul Indelicato José Pires Marques José Paulo Santos 《X射线光谱测定》2019,48(5):351-359
We report on measurements of the Kβ diagram, valence-to-core (VtC), and hypersatellite X-ray spectra induced in metallic Cr by photon single and double K-shell ionization. The experiment was carried out at the Stanford Synchrotron Radiation Lightsource using the seven-crystal Johann-type hard X-ray spectrometer of the beamline 6-2. For the Kβ diagram and VtC transitions, the present study confirms the line shape features observed in previous works, whereas the Khβ hypersatellite transition was found to exhibit a complex spectral line shape and a characteristic low-energy shoulder. The energy shift of the hypersatellite relative to the parent diagram line was deduced from the measurements and compared with the result of extensive multiconfiguration Dirac–Fock (MCDF) calculations. A very good agreement between experiment and theory was found. The MCDF calculations were also used to compute the theoretical line shape of the hypersatellite. A satisfactory agreement was obtained between the overall shapes of the experimental and theoretical spectra, but deviations were observed on the low- and high-energy flanks of the hypersatellite line. The discrepancies were explained by chemical effects, which were not considered in the MCDF calculations performed for isolated atoms. 相似文献
17.
N. S. Pavlov V. A. Galkin I. A. Nekrasov E. Z. Kurmaev 《Physics of the Solid State》2009,51(11):2207-2210
A numerical electronic band structure calculations for sulfides NiS, CuS, and ZnS are carried out. Using the results a detailed
analysis of a valence states is performed; obtained partial densities of states are compared with X-ray SL
2,3 and $
SK_{\beta _{1,3} }
$
SK_{\beta _{1,3} }
-emission spectra. We showed that spectrum lineshape depends on hybridization strength between various Me(3d)-orbitals and 3p-states of sulfur. The hybridization strength and the symmetry of hybrid Me(3d)-orbitals are defined by crystal lattice structure. Finally a well splitted in energy bonding and antibonding states Me(3d)-S(3p) appear while weakly hybridized Me(3d)-states mainly contribute to spectra intensity in the energy between them. A good agreement between the theoretical and the
experimental spectra of valence band for considered sulfides is obtained. 相似文献
18.
M.?Mahgoub R.?Krücken Th.?Faestermann A.?Bergmaier D.?Bucurescu R.?Hertenberger Th.?Kr?ll H.?-F.?Wirth A.?F.?Lisetskiy 《The European Physical Journal A - Hadrons and Nuclei》2009,40(1):35-43
The reaction 54Fe(, p)55Fe was studied at the Munich Q3D spectrograph with a 14MeV polarized deuteron beam. Excitation energies, angular distributions
and analyzing powers were measured for 39 states up to 4.5MeV excitation energy. Spin and parity assignments were made and
spectroscopic factors deduced by comparison to DWBA calculations. The results were compared to predictions by large-scale
shell model calculations in the full pf -shell and it was found that reasonable agreement for energies and spectroscopic factors below 2.5MeV could only be obtained
if up to 6 particles were allowed to be excited from the f
7/2 orbital into p
3/2 , f
5/2 , and p
1/2 orbitals across the N = 28 gap. For levels above 2.5MeV the experimental strength distribution was found to be significantly more fragmented than
predicted by the shell model calculations. 相似文献
19.
Summary Room temperature optical-reflectivity measurements on some transition metal thiophosphates were carried out in the near infrared
and visible regions. The resulting spectra, interpreted on the basis of the ?transition metal weakly interacting? model, agree
well with earlier optical transmission measurements. Below the fundamental absorption edge, the observed features have been
assigned to 3d–3d transitions occurring on the transition metal ion, while those observed at photon energies greater than the absorption threshold
have been attributed to transitions from the valence bands to discrete 3d orbital levels or to the conduction bands. A more detailed information on the metal ion 3d levels energy distribution with respect to the valence band states belonging to the (P2S6)4- cluster and a more precise determination of the MPS3 absorption edge energy position have been obtained. 相似文献
20.
Chihiro Suzuki Izumi Murakami Fumihiro Koike Takeshi Higashiguchi Hiroyuki A. Sakaue Naoki Tamura Shigeru Sudo Gerry O'Sullivan 《X射线光谱测定》2020,49(1):78-84
We are developing an experimental database of extreme ultraviolet spectra from highly charged ions using optically thin high-temperature plasmas produced in the Large Helical Device. Spectra from a variety of elements with atomic numbers ranging from 36 to 83 have been systematically recorded in the range of 1–20 nm by a grazing incidence spectrometer. For higher Z elements from tin onward, discrete or quasicontinuum spectral features from n=4 (N-shell) ions are mainly observed depending upon the plasma temperature, which leads to some new experimental identifications of spectral lines. On the other hand, major emitters are n=3 (M-shell) ions for medium Z elements from krypton to ruthenium. The calculated wavelengths for Δn≠0 transitions agree well with the measurements and the calculated wavelengths are systematically shifted to shorter wavelengths for Δn=0 transitions associated with inner-subshell excited configurations. 相似文献