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Tytuł:
Cross Sections for l-Mixing of K(n$\text{}^{2}$F) States in Collisions with Ground-State K(4$\text{}^{2}$S) Atoms
Autorzy:
Głódź, M.
Huzandrov, A.
Klavins, J.
Sydoryk, I.
Szonert, J.
Gateva-Kostova, S.
Kowalski, K.
Powiązania:
https://bibliotekanauki.pl/articles/2014246.pdf
Data publikacji:
2000-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.50.Fa
Opis:
We report measurements of the cross sections σ$\text{}_{l-mix}$ for angular momentum mixing of the K(n$\text{}^{2}$F)(n=6, 7, 8) states with the K(n,l > 3) states, induced in thermal collisions with parent ground state K(4$\text{}^{2}$S) atoms. The experiment was performed in a cell heated to ca. 450K. The n$\text{}^{2}$F states were excited in two steps: 4$\text{}^{2}$S → 4$\text{}^{2}$P → n$\text{}^{2F}$ by using a diode laser for the first step (a dipole-transition) and a pulsed dye laser for the second step (a quadrupole-transition). The measured values σ$\text{}_{l-mix}$ (6$\text{}^{2}$F)=3.6+-2.2, σ$\text{}_{l-mix}$ (7$\text{}^{2}$F)=4.2+-2.6 and σ$\text{}_{l-mix}$ (8$\text{}^{2}$F)=8.0+-4.6 (in units of 10$\text{}^{-13}$cm$\text{}^{-1}$) are close to the corresponding values of the geometrical cross sections.
Źródło:
Acta Physica Polonica A; 2000, 98, 4; 353-361
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vacancy Transfer Probabilities from K to L Shell for Low Atomic Number Elements at 5.96 keV
Autorzy:
Ertuğral, B.
Baltaş, H.
Çelik, A.
Kobya, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1537681.pdf
Data publikacji:
2010-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.80.-t
33.20.Rm
Opis:
Vacancy transfer probabilities from K to L shell were measured using $I_{Kβ}//I_{Kα}$ intensity ratios for six elements in the atomic region 16 ≤ Z ≤ 22. The K X-rays from the targets excited by 5.96 keV (1.85 GBq $\text{}^{55}Fe$ filtered annular source) incident photon were obtained using a high resolution PGT model Si(Li) detector. Theoretical values were calculated using radiative and radiationless transition rates of these elements. The measured values of $η_{KL}$ were compared with the theoretical ones. Reasonable agreement was typically obtained between present and theoretical values.
Źródło:
Acta Physica Polonica A; 2010, 117, 6; 900-903
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
XANES Studies of Mn K and $L_{3,2}$ Edges in the (Ga,Mn)As Layers Modified, by High Temperature Annealing
Autorzy:
Wolska, A.
Lawniczak-Jablonska, K.
Klepka, M.
Jakieła, R.
Demchenko, I.
Sadowski, J.
Holub-Krappe, E.
Persson, A.
Arvanitis, D.
Powiązania:
https://bibliotekanauki.pl/articles/1812244.pdf
Data publikacji:
2008-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Dm
75.50.Pp
Opis:
$Ga_{1-x}Mn_xAs$ is commonly considered as a promising material for microelectronic applications utilizing the electron spin. One of the ways that allow increasing the Curie temperature above room temperature is to produce second phase inclusions. In this paper $Ga_{1-x}Mn_xAs$ samples containing precipitations of ferromagnetic MnAs are under consideration. We focus on the atomic and electronic structure around the Mn atoms relating to the cluster formation. The changes in the electronic structure of the Mn, Ga and As atoms in the (Ga,Mn)As layers after high temperature annealing were determined by X-ray absorption near edge spectroscopy. The experimental spectra were compared with the predictions of ab initio full multiple scattering theory using the FEFF 8.4 code. The nominal concentration of the Mn atoms in the investigated samples was 6% and 8%. We do not observe changes in the electronic structure of Ga and As introduced by the presence of the Mn atoms. We find, in contrast, considerable changes in the electronic structure around the Mn atoms. Moreover, for the first time it was possible to indicate the preferred interstitial positions of the Mn atoms.
Źródło:
Acta Physica Polonica A; 2008, 114, 2; 357-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric Amplification in Magnetized Nondegenerate Semiconducting Plasmas
Autorzy:
Jat, K. L.
Neogi, A.
Ghosh, S.
Powiązania:
https://bibliotekanauki.pl/articles/1887743.pdf
Data publikacji:
1991-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.Ky
72.20.Ht
73.50.Rb
78.20.Hp
Opis:
Using the straightforward coupled-mode theory, the parametric amplification is analytically investigated in magnetized piezoelectric as well as non-piezoelectric semiconductors. The origin of nonlinear interaction is taken to be in the second-order optical susceptibility χ$\text{}^{(2)}$ arising from the nonlinear induced current density. The threshold value of the pump electric field E$\text{}_{0th}$ is obtained for crystals. E$\text{}_{0th}$ is found to decrease with the rise in magnetic field and fall with the rise in scattering angle. Parametric gain constants are obtained for different situations of practical interest, i.e. (i) for piezoelectric coupling only g$\text{}_{p}$, (ii) for deformation potential coupling only g$\text{}_{d}$, (iii) for both the couplings g$\text{}_{b}$. Numerical investigations reveal that the magnetic field increases the gain. Maximum gains are obtained for backward scattered mode. g$\text{}_{d}$ is always found to be less than g$\text{}_{p}$ and g$\text{}_{b}$. It is also found that g$\text{}_{p}$ and g$\text{}_{b}$ both are identical up to k ≈ x 10$\text{}^{7}$m$\text{}^{-1}$ and for k ≥ 3 x 10$\text{}^{7}$m$\text{}^{-1}$, g$\text{}_{b}$ exceeds g$\text{}_{p}$.
Źródło:
Acta Physica Polonica A; 1991, 79, 6; 829-841
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect on Highly Cr-Substituted Manganite Nd$\text{}_{0.6}$C a$\text{}_{0.4}$(Mn$\text{}_{0.5}$Cr$\text{}_{0.5}$)O$\text{}_{3}$
Autorzy:
Gamari-Seale, H.
Troyanchuk, I. O.
Bushinsky, M. V.
Stefanopoulos, K. L.
Hernandez-Velasco, J.
Powiązania:
https://bibliotekanauki.pl/articles/2037098.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.25.+z
75.30.Kz
75.47.Lx
Opis:
Neutron powder-diffraction experiments on the highly Cr-substituted manganite, Nd$\text{}_{0.6}$Ca$\text{}_{0.4}$(Mn$\text{}_{0.5}$Cr$\text{}_{0.5}$)O$\text{}_{3}$, at different temperatures and fields reveal that the structure retains the charge exchange-type of the parent compound, Nd$\text{}_{0.6}$Ca$\text{}_{0.4}$MnO$\text{}_{3}$. It is antiferromagnetic below 200 K and becomes a canted antiferromagnet below 50 K. The Mn and Cr form zig-zag ferromagnetic chains coupled antiferromagnetically in the ac-plane. These are stacked along the b-axis with opposite spins.
Źródło:
Acta Physica Polonica A; 2004, 105, 1-2; 81-86
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physical Characterization of $Sb_2O_3-M_2O-MoO_3$ (M~= Li,~K) New Glasses
Autorzy:
Soltani, M.
Hamzaoui, M.
Houhou, S.
Touiri, H.
Bediar, L.
Ghemri, A.
Petkova, P.
Powiązania:
https://bibliotekanauki.pl/articles/1399699.pdf
Data publikacji:
2013-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Ce
78.20.Ci
78.30.-j
Opis:
New heavy metal oxide glasses involving $Sb_2O_3$ have been investigated. By using classical routes (melting-casting), glasses synthesized in silica crucibles were obtained in the combination of ternary systems $Sb_2O_3-M_2CO_3-MoO_3$ (M = Li and K). Characteristic temperatures such as glass transition $T_{g}$, and onset of the crystallization $T_{x}$, have been measured using differential scanning calorimeter. Ultrasonic velocities were measured by using pulse echo method to determine the elastics parameters, such as elastic modules (E, G, K, L). Other physical properties were measured, such as density and optical transmission window in far infrared spectra using KBr pellets. Influence of composition on these physico-chemical properties is discussed and correlated to the glass structure.
Źródło:
Acta Physica Polonica A; 2013, 123, 2; 227-229
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Properties of InAs/GaAs Self-Assembled Quantum Dot Structures and Devices Studied by Photocurrent Spectroscopy
Autorzy:
Mowbray, D. J.
Fry, P. W.
Skolnick, M. S.
Itskevich, I. E.
Harris, L.
Ashmore, A. D.
Finley, J. J.
Wilson, L. R.
Schumacher, K. L.
Barker, J. A.
O'Reilly, E. P.
Al-Khafaji, M.
Cullis, A. G.
Hopkinson, M.
Clark, J. C.
Hill, G.
Powiązania:
https://bibliotekanauki.pl/articles/2014190.pdf
Data publikacji:
2000-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Fd
73.61.Ey
73.50.Pz
42.55.Px
Opis:
The power of photocurrent spectroscopy to study the electronic properties of InAs/GaAs self-assembled quantum dots is described. From comparison of results from different samples it is shown that photocurrent provides a direct means to measure absorption spectra of quantum dots. Studies in high electric field enable the electron-hole vertical alignment to be determined. Most surprisingly this is found to be opposite to that predicted by all recent predictions. Comparison with theory shows that this can only be explained if the dots contain significant amounts of gallium, and have a severely truncated shape. The nature of the ground and excited state transitions, carrier escape mechanisms from dots, in-plane wave function anisotropies and the modal gain of a quantum dot laser are determined.
Źródło:
Acta Physica Polonica A; 2000, 98, 3; 279-293
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Optics of Atomic Wave-Packets
Autorzy:
Rzążewski, K.
Plaja-Rustein, L.
Pumares-Carceller, L.
Roso-Franco, L.
Żakowicz, W.
Powiązania:
https://bibliotekanauki.pl/articles/1931537.pdf
Data publikacji:
1994-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.50.Md
42.50.Vk
Opis:
Recent progress in production and control of the atomic wave-packets calls for re-examination of the most fundamental quantum optical processes. We have examined the evolution of the atomic wave-packet resonantly driven by the monochromatic laser beam and the spontaneous emission from an extended atom. We stress the role of Doppler shifts in the dephasing of the atomic dipole. New effects of single laser pulse photon echo and homogeneous Doppler modification of the emission line are discussed.
Źródło:
Acta Physica Polonica A; 1994, 86, 1; 279-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Conductivity Effects in Bi₂TeO₅ Single Crystals
Autorzy:
Agarkov, K.
Sadovskaya, L.
Powiązania:
https://bibliotekanauki.pl/articles/1031021.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
Opis:
The current-voltage characteristics (I-V) of non-stoichiometric bismuth tellurite crystals were studied in a range of temperatures from 150°C to 350°C and fields up to 2.5 kV/cm with asymmetric contacts (In-Ga eutectic and Na₂SiO₃). The I-V curves and observed monopolar injection are described by the approximation of space charge limited currents. In the composition of 47% Bi₂O₃-53% TeO₂ electronic conduction is prevailed. In the composition 43% Bi₂O₃-57% TeO₂ the conductivity is contributed by electrons and holes. The spectrum of local states in the band gap of the studied crystals is quasicontinuous, which cannot be described by models of a discrete or exponential distribution.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 940-942
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hydrogen and its Complexes in Silicon
Autorzy:
Dobaczewski, L.
Bonde Nielsen, K.
Gosciński, K.
Andersen, O.
Powiązania:
https://bibliotekanauki.pl/articles/2014151.pdf
Data publikacji:
2000-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Lq
71.55.Cn
68.55.Ln
Opis:
In this study the technique of Laplace transform (high resolution) deep level transient spectroscopy combined with the uniaxial stress method has been used to study a symmetry and the defect reconfiguration kinetics (the stress induced alignment) of some forms of hydrogen-related centres. We have confirmed the trigonal symmetry of the defect related to the isolated bond centred hydrogen. When hydrogen decorates the vacancy-oxygen pair (the A centre) the apparent defect orthorhombic symmetry is not lowered as a result of a very high hydrogen jumping rate between two unsaturated broken bonds of the vacancy. We also show that the stress-induced defect alignment in some cases can be related to the same microscopic mechanism of the hydrogen motion as it is for the diffusion process.
Źródło:
Acta Physica Polonica A; 2000, 98, 3; 231-239
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiconductor Superlattices with Small Band Offsets - feature article
Autorzy:
Yang, G.
Lewandowski, L. A.
Furdyna, J. K.
Ram-Mohan, L. R.
Powiązania:
https://bibliotekanauki.pl/articles/1968871.pdf
Data publikacji:
1998-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
Opis:
Optical transitions in small band offset superlattices are studied within the framework of the nearly free electron approximation, in which the weak superlattice potential is treated as a perturbation. Interband selection rules are derived for transitions involving conduction and valence band states at the superlattice Brillouin zone center and the zone edge. It is found that a number of new transitions can occur in such small-offset superlattices due to wave function mixing of different subband states. The effect of the effective mass on the optical transitions is also discussed. The theory is used to explain the results observed in magneto-optical absorption experiment in ZnSe/Zn$\text{}_{1-x}$Mn$\text{}_{x}$Se small-offset superlattices. Furthermore, the nearly free electron formulation is found to be in excellent agreement with rigorous multi-band numerical calculation on superlattices involving small band offsets.
Źródło:
Acta Physica Polonica A; 1998, 93, 4; 567-600
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trap Spectra of Annealed Quartz
Autorzy:
Chruścińska, A.
Oczkowski, H. L.
Przegiętka, K. R.
Powiązania:
https://bibliotekanauki.pl/articles/1945395.pdf
Data publikacji:
1996-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Kn
Opis:
The trap energy density spectra of natural quartz were investigated by the fractional glow technique. The thermal treatment before excitation induces the changes of thermoluminescence sensitivity as well as the changes of trap spectrum. After annealing at temperature higher than 400°C, a new kind of trap is observed. The frequency factor was determinated by the fitting of the theoretical glow curve calculated using the trap depth measured by fractional glow technique to experimental one.
Źródło:
Acta Physica Polonica A; 1996, 89, 4; 555-568
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoinduced Conversion of Hybridization in Graphite
Autorzy:
Radosinski, L.
Luty, T.
Nasu, K.
Ohnishi, H.
Nishioka, K.
Radosz, A.
Wójt, D.
Powiązania:
https://bibliotekanauki.pl/articles/1490005.pdf
Data publikacji:
2012-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.30.Hd
61.66.-f
Opis:
Recent experiments indicate that a photostimulated graphite with a femtosecond laser pulse results in the formation of a stable domain with sp^3 like interlayer bonds. By means of the energy barrier minimization and molecular dynamics using the empirical Brenner potential we study a geometrical structure of the new phase. We clarify proliferation of the initial domain and prove that the overall process is a multiphoton one. Furthermore, we present a model describing the initial transformation - an interlayer charge transfer resulting in the localization of an exciton-like state. The local density approximation electronic structure analysis reveals that the electronic state of the new phase is an insulator immersed in semimetal. We study by means of the long-range carbon bond order potential the effect of the existence of the new phase on the surrounding graphite and propose a new mid step structure on the path of a photoinduced graphite-diamond conversion.
Źródło:
Acta Physica Polonica A; 2012, 121, 2; 359-368
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MBE Growth and Properties of ZnYbTe Layers
Autorzy:
Sadowski, J.
Szamota-Sadowska, K.
Świątek, K.
Kowalczyk, L.
Abounadi, A.
Rajira, A.
Powiązania:
https://bibliotekanauki.pl/articles/1952684.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
61.14.Hg
Opis:
The MBE grown ZnYbTe layers were characterized by X-ray diffraction, photoluminescence and reflectivity measurements. The MBE growth conditions allowing to obtain monocrystalline ZnYbTe layers were found to be metal-rich (MBE growth with excess of Zn flux). In optical measurements (photoluminescence, reflectivity), both transitions connected with ternary ZnYbTe compound and with Yb$\text{}^{3+}$ ions were detected. The quality of ZnYbTe layers with Yb content of 3% and 1% is inferior to the quality of pure ZnTe MBE layers, which is clearly seen in the results of photoluminescence and reflectivity measurements. In the ZnYbTe layers with 3% Yb, exhibiting monocrystalline character in reflection high-energy electron diffraction and X-ray diffraction measurements, optical transitions characteristic of pure YbTe were detected. In ZnYbTe layers with 1% Yb, no transitions connected with YbTe were observed.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 1060-1064
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Graphical Interface to the MOSGRAF Suite
Autorzy:
Duraj, Ł.
Ruebenbauer, K.
Powiązania:
https://bibliotekanauki.pl/articles/1506654.pdf
Data publikacji:
2011-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
76.80.+y
07.05.Kf
Opis:
A contribution is devoted to the recent development of the MOSGRAF suite used to process Mössbauer data and to generate reference functions for the modern spectrometers of the MsAa-x (x=1, 2, 3, 4) family. Newly developed interface is designed for the Microsoft Windows-XP® or higher system of this class. However one can use some older system of this class as well provided some plug-ins are installed additionally. The lowest useable system is Microsoft Windows-98® - 32-bit edition. The new version of the MOSGRAF suite is compatible with 32-bit and 64-bit systems. MOSGRAF is fully compatible with MsAa-x spectrometers, however a powerful tool to convert ASCII data files from other spectrometers is provided. Data processing programs are compiled by the high efficiency Fortran-90 Lahey-Fujitsu® compiler. One of the most important new features is the ability to process velocity calibration data obtained by the new method based on the measurement of the time lapse between fringes of the Michelson-Morley interferometer.
Źródło:
Acta Physica Polonica A; 2011, 119, 1; 75-77
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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