Temat: 71.70.Ch - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Spin-Orbit Coupling for f-Electrons in a Crystalline Field
Autorzy:: Lulek, T.
Tematy:: 71.70.Ch; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1929779.pdf Link otwiera się w nowym oknie
Opis:: The notion of a spin-orbit interaction arises from consideration of dynamics of multielectron atoms, i.e. systems of N electrons in a spherical potential. This notion is essentially a single-particle one. We sketch its origin as a second-order correction when Dirac four-component wave equations for an electron in external electromagnetic fields are simplified to the two-component Pauli spinors. The constraints in spinorial degrees of freedom consist, roughly speaking, in neglecting the small component of the electron four-function. The spin-orbit interaction term serves to compensate effects of the small component. The crystalline field induces some deviations from spherical symmetry of an isolated atom, which yields some modifications of the spherical form of the spin-orbit interaction operator. These modifications can be described in terms of a number of tensor operators adapted to appropriate chains of subgroups of the spherical symmetry group. We present a classification of independent tensor operators and discuss the relevant parameters for f-ions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Rationalization of Spectra of Rare Earths in Condensed Matter
Autorzy:: Reisfeld, R.
Jørgensen, C. K.
Tematy:: 71.70.Ch; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1929810.pdf Link otwiera się w nowym oknie
Opis:: The parametrized models are compared with counter-intuitive consequences of the non-relativistic Schrödinger treatment. For both 4f$\text{}^{ q}$, 5f$\text{}^{ q}$ and d$\text{}^{9}$ systems in condensed matter, the energy levels must be strongly influenced by correlation effects. The parametrization of intensities is conceptually very different for f$\text{}^{ q}$ and d$\text{}^{9}$ compounds. The bandwidths of absorption and luminescence are discussed and related to the Born-Oppenheimer factorization.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Parametrization of the Bilinear Orbit—Lattice Interaction
Autorzy:: Pastusiak, W.
Tematy:: 71.70.Ch; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1888013.pdf Link otwiera się w nowym oknie
Opis:: A group theoretical parametrization scheme of the bilinear orbit-lattice interaction is presented. Using this scheme a general analytical form of this interaction in the point-charge electrostatic model has been obtained. Based on this general analytical form the second-order parameters of the bilinear orbit-lattice interaction have been calculated for a tetrahedral complex. For cubic complexes a microscopic interpretation of the G-tensor components in the long-wavelength approximation of acoustic waves is given for the first time. The presented scheme of parametrization as well as the method of calculations of the interaction parameters may be extended to other models of the crystal field.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Electronic Structure of Organometallic Complexes of f Elements. Are Molecular Orbital Calculations a Useful Tool for Spectroscopists?
Autorzy:: Jank, S.
Amberger, H.-D.
Tematy:: 03.65.Sq
71.70.Ch; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1945458.pdf Link otwiera się w nowym oknie
Opis:: The crystal field parameters of base-free (Me$\text{}_{3}$SiC$\text{}_{5}$H$\text{}_{4}$)$\text{}_{3}$Pr, (C$\text{}_{5}$H$\text{}_{5}$)$\text{}_{3}$Pr·NCCH$\text{}_{3}$, (C$\text{}_{5}$H$\text{}_{5}$)$\text{}_{3}$La(NCCH$\text{}_{3}$)$\text{}_{2}$:Pr, [Pr(C$\text{}_{8}$H$\text{}_{8}$)]$\text{}^{+}$ and Nd[N(SiMe$\text{}_{3}$)$\text{}_{2}$]$\text{}_{3}$ as model compound for Nd[CH(SiMe$\text{}_{3}$)$\text{}_{2}$]$\text{}_{3}$ were inserted into the corresponding energy matrices of a model spin-free f$\text{}^{1}$ system. Diagonalizing these matrices the crystal field splitting patterns of the f orbitals were calculated. These experimentally based molecular orbital schemes are compared with the results of previous model calculations.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Low Temperature Magnetic Ordering in NdAgAl₃
Autorzy:: Nallamuthu, S.
Džubinská, A.
Reiffers, M.
Nagalakshmi, R.
Tematy:: 71.70.Ch
65.40.Ba; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1032835.pdf Link otwiera się w nowym oknie
Opis:: We present the detailed study of magnetic, thermodynamic, and transport properties of polycrystalline NdAgAl₃. The compound crystallizes in BaNiSn₃-type tetragonal structure with the space group I4mm. Magnetic, heat capacity and transport measurements indicate the possible antiferromagnetic nature of the ordering below 2 K. The compound shows the Schottky anomaly in heat capacity data. Magnetoresistance is negative at low temperature.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: A Theoretical Analysis of Zero Field Splitting of $Mn^{2+}$ in Ammonium Oxalate Monohydrate
Autorzy:: Kripal, R.
Pandey, S.
Tematy:: 71.70.Ch
76.30.Fc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1535738.pdf Link otwiera się w nowym oknie
Opis:: The superposition model has been used to investigate the substitution of $Mn^{2+}$ in ammonium oxalate monohydrate. The zero field splitting parameters D and E calculated by the superposition model are compared with the experimental values $D_{exp}$ and $E_{exp}$, respectively, for $Mn^{2+}$ obtained by electron paramagnetic resonance. Both the zero field splitting parameters D and E calculated theoretically are in good agreement with the experimental values $D_{exp}$ and $E_{exp}$. The result indicates that the $Mn^{2+}$ ion substitutes for the $NH_4^{+}$ ion in ammonium oxalate monohydrate.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Point-Contact Spectroscopy of Ce$\text{}_{1-x}$RE$\text{}_{x}$Ni$\text{}_{5}$ (RE = Pr, Nd)
Autorzy:: Kačmárová, T.
Reiffers, M.
Garcia Soldevilla, J.
Goméz Sal, J. C.
Espeso, J. I.
Blanco, J. A.
Tematy:: 73.40.Jn
71.70.Ch
71.70.Gm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2013409.pdf Link otwiera się w nowym oknie
Opis:: We report on the study of the electron-quasiparticle interaction function in Ce$\text{}_{1-x}$RE$\text{}_{x}$ Ni$\text{}_{5}$ (RE = Pr, Nd) pseudobinary compounds for x = 0, 0.2, 0.5, 0.8, and 1 measured by means of point-contact spectroscopy. The measured point-contact spectra (d$\text{}^{2}$V/dI$\text{}^{2}$ - directly proportional to the electron- quasiparticle interaction function) of the heterocontacts between Ce$\text{}_{1-x}$ RE$\text{}_{x}$Ni$\text{}_{5}$ and Cu in the ballistic regime are presented.zapisz i p
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Crystal Field Analysis of $Cr^{3+}$ Doped $SrAl_{2}O_{4}$ Spinel
Autorzy:: Stanciu, M.
Ciresan, M.
Avram, N.
Tematy:: 71.70.Ch
68.47.Jn
71.70.Gm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1791232.pdf Link otwiera się w nowym oknie
Opis:: The present work is devoted to the crystal field analysis of trivalent chromium doped in $SrAl_{2}O_{4}$ spinel in the frame of the exchange charge model of crystal field. Using the shell model and pair approximation, we optimize the geometric structure of the crystal. The approach enables the modeling of the crystal field parameters and thus calculates the energy level scheme of $Cr^{3+}$ ions in spinel $SrAl_{2}O_{4}$. The obtained results are compared with experimental data and discussed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Electronic Structure of $PrCo_2Ge_2$
Autorzy:: Diviš, M.
Vejpravová, J.
Rusz, J.
Prokleška, J.
Sechovský, V.
Tematy:: 71.15.Mb
71.70.Ch; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1813659.pdf Link otwiera się w nowym oknie
Opis:: The intermetallic compound $PrCo_2Ge_2$ exhibits very interesting physical properties: antiferromagnetism below $T_N$ = 28 K, an order to order transition at $T_R$ = 8 K, a rich magnetic phase diagram, and huge magnetocrystalline anisotropy as observed by recent experiments on a single crystal in a magnetic field up to 14 T. We performed first principles calculations based on the density functional theory. The localized $4f^2$ configuration of $Pr^{3+}$ was treated using the open core approximation. The electronic densities of states were obtained and the position of the Fermi level was found. The hybridization between the Co-3d, Pr-5d and Ge-4p states is discussed. The calculated magnetic moment of Co is found to be quite small $(m_{Co} < 0.1 μ_B)$. The first principles calculations of the crystal field interaction were performed as well: the obtained crystal field parameters were used as the starting parameters for further refinement in comparison with experimental data of the magnetic susceptibility and specific heat. The crystal field splitting of the 4f states was determined.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Crystal Field Analysis of Cr$\text{}^{3+}$ Energy Levels in LiGa$\text{}_{5}$O$\text{}_{8}$ Spinel
Autorzy:: Brik, M. G.
Avram, N. M.
Avram, C. N.
Tematy:: 42.70.Hj
71.70.Ch; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2047880.pdf Link otwiera się w nowym oknie
Opis:: Detailed and consistent crystal field analysis of the LiGa$\text{}_{5}$O$\text{}_{8}$:Cr$\text{}^{3+}$ absorption spectrum is performed in the present paper by using the exchange charge model of crystal field. We calculate the crystal field parameters from the crystal structure date and diagonalize the crystal field Hamiltonian to obtain the energy level structure of Cr$\text{}^{3+}$ ions in LiGa$\text{}_{5}$O$\text{}_{8}$. The obtained energy levels and estimated Racah parameters B and C were compared with the experimental spectroscopic data; good agreement was demonstrated.
Dostawca treści:: Biblioteka Nauki

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