Autor: Avram, N. - Prolib Integro

Skocz do pozycji: 1.

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

Artykuł

Skocz do pozycji: 2.

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

Artykuł

Skocz do pozycji: 3.

Tytuł:: Calculation of Optical and Spin-Hamiltonian Parameters for $Mn^{4+}$ Doped in $LiGa_{5}O_{8}$
Autorzy:: Ciresan, M.
Stanciu, M.
Avram, N.
Tematy:: 74.25.Jb
74.25.nd
76.30.-v; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1791234.pdf Link otwiera się w nowym oknie
Opis:: The aim of this paper is to investigate, from theoretical point of view, the optical spectra and EPR (g-factors) parameters for $Mn^{4+}:LiGa_{5}O_{8}$. The optical energy levels scheme has been obtained by the diagonalization of the Hamiltonian of the system, using all 50 wave functions of the LS terms of $3d^{3}$ electron configuration. The crystal field parameters have been obtained in the exchange charge model of crystal field, taking into account the structure of the host matrix and effects of the covalent bond formation between the $Mn^{4+}$ with $O^{2-}$. The satisfactory agreement with experimental data is obtained.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 4.

Tytuł:: Long-Range Correlation in Atomic Vibration οf Chicken Lysozyme Backbone
Autorzy:: Crăciun, D.
Isvoran, A.
Avram, N.
Tematy:: 05.45.-a
82.35.Pq
87.15.hm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1795703.pdf Link otwiera się w nowym oknie
Opis:: Within this study we use methods such as spectral analysis that gives the spectral coefficient β, detrended fluctuations analysis that gives the scaling exponent α and the determination of Hurst exponent (H) to analyze the spatial series corresponding to the temperature factors of N, C-alpha, C and O atoms of 14 complexes of the chicken lysosyme. The mean values of the investigated parameters obtained for the 14 complexes are: β=1.779 ± 0.086, α=1.382 ± 0.009 and H=0.916. These values reveal long-range correlation in atomic vibrations corresponding to the chicken lysozyme backbone.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 5.

Tytuł:: Comparative Study between Energy Levels of $Cr^{3+}$ and $Co^{2+}$ Ions Doped in $MgF_{2}$ Crystal
Autorzy:: Nistora, R.
Andreici, L.
Avram, N.
Tematy:: 71.70.Ch
42.70.Hj
61.72.S-; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1791222.pdf Link otwiera się w nowym oknie
Opis:: The aim of this paper is to present a comparison of the energy level schemes of $Cr^{3+}$ ($3d^{3}$ electrons) and $Co^{2+}$ ($3d^{7}$ electrons), each of ions doped, separately, in $MgF_{2}$ crystal. We report on the detailed and consistent crystal field analysis of $Cr^{3+}$ spectra in $MgF_{2}$ crystal and compare with results, previously obtained, for $Co^{2+}$, doped in same host matrix. The results are based on application of the exchange charge model of crystal field to the calculation of crystal field parameters and energy levels of both ions doped in $MgF_{2}$.The calculations have been performed on previously optimized geometry of $MgF_{2}$ crystal. The obtained results are compared with experimental data and discussed.
Dostawca treści:: Biblioteka Nauki

Artykuł

Skocz do pozycji: 6.

Tytuł:: Angular Distortion around $Cr^{3+}$ Ions Doped Diammonium Hexaaqua Magnesium Sulphate Single Crystal
Autorzy:: Ciresan, M.
Vaida, M.
Avram, N.
Tematy:: 75.10.Dg
76.30.-v
71.70.Ch; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1815473.pdf Link otwiera się w nowym oknie
Opis:: The aim of the present study is to explain the local distortion around $Cr^{3+}$ ions doped in the title crystal using the latest experimental data regarding optical and EPR spectra. We calculated $g_ǁ$, $g_⊥$, and D spin-Hamiltonian parameter as function of angle between the $C_3$ axis and metal-ligand chemical bond in local distorted octahedral cluster $[CrO_6]^{9-}$ formed after doped crystal. The method is based on the single spin-orbit coupling parameter model, in the cluster approach using Macfarlane high order perturbation formulae. The results compared with experimental data give a reasonable agreement.
Dostawca treści:: Biblioteka Nauki

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