Inversion of 4f-states in CeB6 thermally excited at 430 K

2007 ◽  
Vol 63 (5) ◽  
pp. 683-692 ◽  
Author(s):  
Ryoko Makita ◽  
Kiyoaki Tanaka ◽  
Yoshichika Ōnuki ◽  
Hiroshi Tatewaki
Keyword(s):  
Excited State ◽  
Energy Level ◽  
Ground State ◽  
Electron Density Distribution ◽  
Atomic Orbital ◽  
Energy Levels ◽  
X Ray ◽  
Small Furnace ◽  
Lower Temperature ◽  
Orbital Analysis

The 4f states of Ce in a typical Kondo crystal, CeB6, are split into an excited state Γ7 and the ground state Γ8, with an excitation energy at 560 K. The electron-density distribution of the thermally excited state was measured at 430 K using a four-circle diffractometer equipped with a small furnace. In contrast to the previous results at lower temperature, electrons are transferred from B6 to Ce at 430 K. X-ray atomic-orbital analysis revealed that the 5d-Γ8 orbitals (the energy level of which is similar to that of the B-2p orbitals) are fully occupied and the 4f-Γ7 orbitals are more populated than the 4f-Γ8 orbitals. Fully occupied 5d-Γ8 makes the 4f-Γ8 states unstable and the energy levels of 4f-Γ7 and 4f-Γ8 are inverted.

5d and 4f electron configuration of CeB6 at 340 and 535 K

2008 ◽  
Vol 64 (5) ◽  
pp. 534-549 ◽  
Author(s):  
Ryoko Makita ◽  
Kiyoaki Tanaka ◽  
Yoshichika Ōnuki
Keyword(s):  
Electron Transfer ◽  
Crystal Field ◽  
Ground State ◽  
Room Temperature ◽  
Atomic Orbital ◽  
Energy Levels ◽  
Electron Configuration ◽  
Acta Cryst ◽  
X Ray ◽  
The Difference

X-ray atomic orbital (XAO) analysis revealed that at both temperatures the electrons are transferred from B 2px (= py ) to Ce 5d and 4f orbitals. At 340 K 5d(j = 5/2)Γ8 orbitals are occupied partially, but 4f(j = 5/2)Γ8 orbitals are more populated than 4f(j = 5/2)Γ7 orbitals, in contrast to our observation at 430 K [Makita et al. (2007). Acta Cryst. B63, 683–692]. At 535 K the XAO analysis revealed clearly that the order of the energy levels of 4f(j = 5/2)Γ8 and Γ7 states reversed again and is the same as that at room temperature. It also limited the possible 5d configurations to three models among the nine possible ones. However, the XAO analysis could not decide which of the three models was the best with the present accuracy of the measurement. Two of them have partially and fully occupied 5d(j = 5/2)Γ7 orbitals and the remaining one has a fully occupied 5d(j = 3/2)Γ8 orbital. Since the lobes of 5d(j = 3/2)Γ8 or 5d(j = 5/2)Γ7 orbitals do not overlap with the 4f(j = 5/2)Γ8 orbitals as well as the 5d(j = 5/2)Γ8 orbitals, the order of the energy levels of the 4f(j = 5/2) orbitals became the same as that at room temperature. These results indicate that the crystal field varies with temperature due to the electron transfer from B 2p to Ce 5d orbitals. The difference densities after the spherical-atom refinement at the three temperatures clearly revealed the different combinations of 4f and 5d orbitals which are occupied. In the present study positive peaks due to the 4f electrons appear near the Ce nucleus and those due to 5d orbitals are found in the area outside the 4f peaks. Between the two areas there is a negative area distributed spherically at 340 K. The negative area produced by the contraction of 4f(j = 5/2)Γ8 orbitals seems to reduce the electron repulsion of the 5d(j = 5/2)Γ8 orbitals and helps the 4f(j = 5/2)Γ8 orbitals to remain as the ground state.

scholarly journals X-ray laser lines in nickel-like erbium

2016 ◽  
Vol 94 (8) ◽  
pp. 705-711
Author(s):  
Wessameldin S. Abdelaziz
Keyword(s):  
Ionization Potential ◽  
Excited States ◽  
Ground State ◽  
Energy Levels ◽  
Single Electron ◽  
Electron Densities ◽  
X Ray ◽  
Electron Excited States

Energy levels of 249 excited levels in nickel-like erbium are calculated using the 3s23p63d10 as a ground state and the single electron excited states from n = 3 to n = 4, 5 orbitals, calculations have been performed using FAC code (Gu. Astrophys. J. 582, 1241 (2003). doi:10.1086/344745 ). The populations are calculated over electron densities from 1020 to 1023 cm−3 and electron temperatures 1/2, 3/4 of the ionization potential of Ni-like Er. The gain coefficients of the transitions are calculated.

scholarly journals Muonic x-ray laser assisted by catalyzed fusion of deuterium and tritium

1987 ◽  
Vol 5 (2) ◽  
pp. 393-398 ◽  
Author(s):  
T. Tajima ◽  
S. Eliezer
Keyword(s):  
Excited State ◽  
Photon Energy ◽  
Ground State ◽  
X Ray

The possibility of an X-ray laser by irradiation of muon beams on a thin rod of deuterium-tritium mixture is discussed. The excited state of dtμ-mesomolecules (J, v) = (1, 0) can be induced to make radiative chain transitions with photon energy of 90 eV to the ground state (0, 0), evacuated by fusion.

Modeling the X-ray emissions from the geo-space environment

2020 ◽  
Author(s):  
Tianran Sun
Keyword(s):  
Solar Wind ◽  
Excited State ◽  
Ground State ◽  
Heavy Ion ◽  
High Charge State ◽  
Space Environment ◽  
Neutral Component ◽  
X Ray ◽  
Working Groups ◽  
Solar Wind Charge Exchange

<p>The Earth's magnetosheath is luminous in the soft X-ray band, due to the solar wind charge exchange (SWCX) process. SWCX occurs when a heavy solar wind ion with a high charge state encounters with a neutral component. The heavy ion obtains an electron and gets into an excited state. It then decays to the ground state and emits a photon in the soft X-ray band. Considering that the X-ray emission from the magnetosheath is higher compared to that from the magnetosphere, information about the boundary positions can be derived from an X-ray image of the magnetosheath.</p><p> </p><p>The solar wind - magnetosphere - ionosphere link explorer (SMILE) is a mission jointly supported by ESA and CAS, which aims at exploring the dynamics in the whole system. Soft X-ray Imager (SXI) is expected to provide X-ray images of the magnetosphere. The Modeling Working Group (MWG) is one of the four working groups of SMILE. Studies about the modeling of X-ray emissions as well as the method to derive the boundary positions are two main topics of the MWG. The main progress of MWG will be summarized here. </p>

Assessment of New Composites Containing Polyamide-6 and Lead Monoxide as Shields against Ionizing Photonic Radiation based on Computational and Experimental Methods

2021 ◽  
Author(s):  
Shahryar Malekie ◽  
Hassan Shooli ◽  
Mohammad Amin Hosseini
Keyword(s):  
Energy Level ◽  
Energy Levels ◽  
Xrd Analysis ◽  
Polyamide 6 ◽  
Melt Mixing ◽  
X Ray ◽  
Weight Percentage ◽  
Lead Monoxide ◽  
Photon Sources ◽  
Different Temperatures

Abstract This study aimed to introduce new composites, containing polyamide-6 (PA6) and lead monoxide (PbO), to protect against ionizing photon sources used for diagnostic and therapeutic purposes. Five composites, containing various weight percentages of PbO filler (0, 5, 10, 20, and 50%), were developed in this study. Initially, the numerical attenuation value was estimated using XMuDat program by calculating the mass attenuation coefficients at different energy levels. Next, the samples were synthesized based on the melt-mixing method in a laboratory mixing extruder, and their characteristics were determined by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Finally, experimental radiation attenuation tests were carried out. Based on the SEM results, the acceptable filler weight percentage was up to 20%; however, substantial aggregates formation was observed at the highest weight percentage. The results of XRD analysis showed a higher tendency for crystallization by decreasing the amorphous area, while increasing the filler weight percentage. Moreover, the amount of mass loss was monitored at different temperatures, revealing that the filler incorporation improved the thermal durability of the samples. According to the radiation results, a good agreement was observed between the experimental and computational data, except when aggregates formation was substantial. According to the experimental data, by increasing the lead weight percentage from 0% (crude PA6) to 50%, the half-value layer decreased from 3.13 to 0.17 cm at an energy level of 59 keV and from 7.28 to 4.97 cm at an energy level of 662 keV. Considering these promising results, the applicability of PA6/PbO composites for protection against low- and medium-energy ionizing photon sources must be investigated in future studies.

ENERGY LEVELS OF A POLARON IN A FINITE PARABOLIC QUANTUM WELL

2001 ◽  
Vol 15 (05) ◽  
pp. 527-535 ◽  
Author(s):  
FENG-QI ZHAO ◽  
XI XIA LIANG ◽  
SHILIANG BAN
Keyword(s):  
Excited State ◽  
Variational Method ◽  
Quantum Well ◽  
Ground State ◽  
Transition Energy ◽  
Energy Levels ◽  
Phonon Interaction ◽  
Electron Phonon Interaction ◽  
Hole Energy ◽  
First Excited State

The effects of the electron–phonon interaction on the electron (or hole) energy levels in parabolic quantum well (PQW) structures are studied. The ground state, the first excited state and the transition energy of the electron (or hole) in the GaAs/Al 0.3 Ga 0.7 As parabolic quantum well are calculated by using a modified Lee–Low–Pines Variational method. The numerical results are given and discussed. A comparison between the theoretical and experimental results is made.

The carbon monoxide flame bands

1963 ◽  
Vol 275 (1362) ◽  
pp. 431-446 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Excited State ◽  
High Resolution ◽  
Energy Level ◽  
Vibrational Level ◽  
Ground State ◽  
Fermi Resonance ◽  
Absorption System ◽  
Weak Absorption ◽  
Vibrational Levels

The carbon monoxide flame bands have been photographed under high resolution from an afterglow source. Bands in the wavelength range 3100 to 3800 Å show a pattern which has been reproduced by calculations of the energies of high vibrational levels of the ground state of CO 2 . The structure of this energy level pattern is strongly affected by extensive Fermi resonance in the 1 Σ + g state. The spectrum is emitted by excited CO 2 molecules which radiate to the ground state from the lowest vibrational level and from the v ´ 2 = 1 level of a B 2 state. This excited state lies approximately 46 000 cm -1 above the lowest level of the ground state, an d has an OCO angle of 122 + 2° and a CO bond length of 1*246 ± 0*008 Å. Combination of these results with the work of other authors shows that the excited state is a 1 B 2 state, and that the carbon monoxide flame bands are associated with the weak absorption system of CO 2 at 1475 Å.

PHOTOCURRENT ABSORPTION SPECTROSCOPIC STUDY OF Si0.6Ge0.4/Si QUANTUM WELLS

2006 ◽  
Vol 20 (02) ◽  
pp. 133-140
Author(s):  
SHIHUA HUANG ◽  
FENGMIN WU ◽  
JI LIN ◽  
FANG LU
Keyword(s):  
Energy Level ◽  
Spectroscopic Study ◽  
Quantum Wells ◽  
Valence Band ◽  
Ground State ◽  
State Energy ◽  
Energy Levels ◽  
Absorption Coefficients ◽  
Discrete Energy ◽  
Discrete Energy Level

Absorption spectra of Si 0.6 Ge 0.4/ Si quantum wells are characterized by photocurrent measurements. The absorption coefficients of two different transitions, namely the transition between the Si band states and the discrete energy level in quantum wells, and the interlevel transition in quantum wells are deduced. They are directly proportional to (ℏω-ΔE)3/2 and δ(ℏω-Eeh), respectively. The valence band offsets of Si 0.6 Ge 0.4/ Si interface are 297 meV. The ground state energy levels in valence band and conduction band Si 0.6 Ge 0.4/ Si quantum wells are 37 meV and 23 meV, respectively.

Low lying levels in 81Br

1969 ◽  
Vol 47 (20) ◽  
pp. 2255-2259 ◽  
Author(s):  
M. Salomon ◽  
C. Hojvat
Keyword(s):  
Excited State ◽  
Energy Level ◽  
Excited States ◽  
Ground State ◽  
Level Scheme ◽  
Coulomb Excitation ◽  
Transition Probability ◽  
Energy Level Scheme ◽  
First Excited State

Coulomb excitation of Br targets and the reaction 80Se(p,γ)81Br were used to populate the low lying excited states of 81Br and an energy level scheme is proposed. The reduced transition probability from the ground state to the first excited state of 81Br (276 keV) has been measured to be B(E2) = 410 ± 40 e2 f4.

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