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Wyszukujesz frazę "78.40.-q" wg kryterium: Temat


Tytuł:
Mesure de la Temperature Basees sur l'Observation du Premier Systéme Negatif de l'Azote
Temperature Measurements Based on the First Negative Spectrum of Nitrogen
Autorzy:
Nassar, H.
Czernichowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1929529.pdf
Data publikacji:
1993-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.10.-n
33.20.-t
07.20.Ka
78.40.-q
Opis:
Noisy, non-resolved emission spectra of the (0,0) 391.4 nm N$\text{}_{2}$$\text{}^{+}$ molecular band are employed for the rotational (and in some case vibrational) temperature evaluation in different sources in the range of 320-7900 K when the apparatus function of the recording system is unknown. The following sources are examined: an ovoid-shaped transferred arc at atmospheric pressure, a low-pressure transferred arc, a high-voltage high-pressure electric discharge, a low-pressure radio-frequency discharge, and an atmospheric pressure laminar plasma jet. The described method is based on a normalization of the experimental spectrum with respect to the (0,0) band-head amplitude followed by a point-to-point comparison of the real spectrum with respect to a computer simulated spectrum using the best-square fit criterion. This criterion is found as the good one: the relative error on temperature evaluation had the same order of magnitude as the noise-to-signal ratio, even if the last one was relatively high. It was also found that the rotational and vibrational temperatures in the radio-frequency discharge are very different, which indicates an out of thermodynamic equilibrium characteristic of such a discharge. The proposed method of temperature evaluation is shown as quite precise and simple to use for even the non-spectroscopists.
Źródło:
Acta Physica Polonica A; 1993, 84, 2; 215-228
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Absorption Spectrum of Ni(II) Ions Doped in Lithium Sodium Potassium Sulphate Single Crystal
Autorzy:
Rama Kumar, R.
Venkata Reddy, B. C.
Powiązania:
https://bibliotekanauki.pl/articles/1933457.pdf
Data publikacji:
1995-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.40.-q
78.50.-w
Opis:
The optical absorption spectra of lithium sodium potassium sulphate doped Ni$\text{}^{2+}$ ions at 300 and 77 K was recorded. The observed bands are assigned as transitions from the ground state $\text{}^{3}$A$\text{}_{2g}$(F) to various excited triplet and singlet states of the Ni$\text{}^{2+}$ ion in octahedral symmetry. The splittings observed for the bands $\text{}^{3}$T$\text{}_{1g}$(F) and $\text{}^{3}$T$\text{}_{2g}$(F) at liquid nitrogen temperature have been explained as due to spin-orbit interaction. The oscillator strengths of the transitions were computed from the area under the curves. From a detailed analysis of the bands of the spectrum, the crystal field parameters B, C, Dq and ξ are evaluated.
Źródło:
Acta Physica Polonica A; 1995, 87, 6; 1023-1029
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exciton Electro-Absorption at Non-Zero Wave Vector
Autorzy:
Slawik, M.
Petelenz, P.
Powiązania:
https://bibliotekanauki.pl/articles/1933598.pdf
Data publikacji:
1995-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Jw
78.20.-e
78.40.-q
Opis:
Based on a previously proposed two-dimensional model of a polyacene crystal, the contributions to the electro-absorption signal from different points of the exciton Brillouin zone are calculated. They are shown to differ substantially both in amplitude and in shape. This makes electro-absorption spectra very sensitive to vibronic coupling. On the one hand, the new factor is a potential complication in theoretical interpretations. On the other hand, it favours electro-absorption spectroscopy as a promising experimental tool to study vibronic effects.
Źródło:
Acta Physica Polonica A; 1995, 88, 2; 401-409
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solvatochromic Effect in a Benzimidazole-Based Betaine: Determination of the Dipole Moments and Second-Order Hyperpolarizability
Autorzy:
Ziółek, L.
Palewska, K.
Lipiński, J.
Sworakowski, J.
Nes̆půrek, S.
Böhm, S.
Meister, E. C.
Powiązania:
https://bibliotekanauki.pl/articles/1933559.pdf
Data publikacji:
1995-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.70.Jk
33.20.-t
42.65.An
78.40.-q
Opis:
Results of measurements of the solvent-dependent shift of the low-energy absorption band solvatochromic effect in a benzimidazole-based betaine are reported in the paper. Measurements of absorption spectra in several solvents of different polarities were performed. The solvatochromic shift of the low-lying absorption band was found to exceed 3000 cm$\text{}^{-1}$; the results obtained were then employed to calculate the ground- and excited-state dipole moment of the molecule. The spectroscopic measurements were supplemented by measurements of the ground-state dipole moment. A remarkable change in the charge distribution was found to occur upon the electronic excitation: both the experimental results and the calculations indicate that the ground-state dipole moment is close to 13 D, whereas in the excited state it amounts to ca. 3 D. The second-order hyperpolarizability of the molecule was calculated from the measurements; its off-resonance value amounts to ca. 20 × 10$\text{}^{-40}$ m$\text{}^{4}$/V (4.8 × 10$\text{}^{-30}$ esu), depending on the solvent used.
Źródło:
Acta Physica Polonica A; 1995, 88, 2; 283-293
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopic Investigations of Charge Transfer Salt VINΦ$\text{}_{2}$(TCNQ)$\text{}_{2}$
Autorzy:
Łapiński, A.
Świetlik, R.
Strzelecka, H.
Veber, M.
Powiązania:
https://bibliotekanauki.pl/articles/1933382.pdf
Data publikacji:
1995-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.38.+i
78.30.Jw
78.40.-q
Opis:
VINΦ$\text{}_{2}$(TCNQ)$\text{}_{2}$ is a salt with two different, non-parallel TCNQ stacks. The polarized reflectance spectra from single crystals in the IR region 660-5200 cm$\text{}^{-1}$, the powder absorption spectra 400-45000 cm$\text{}^{-1}$ and FT-NIR Raman spectra of VINΦ$\text{}_{2}$(TCNQ)$\text{}_{2}$ are measured at room temperature. Moreover, the temperature dependence of powder absorption spectra in the frequency range 400-7900 cm$\text{}^{-1}$ are studied. The nature of electronic bands, the anisotropy of optical conductivity, the temperature dependence of some vibrational bands and the charge distribution on different TCNQ stacks are discussed.
Źródło:
Acta Physica Polonica A; 1995, 87, 4-5; 835-841
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Level Scheme of Nd$\text{}^{3+}$ Ion in Rare Earth Oxyhalides, REOX (X = F, Cl, and Br)
Autorzy:
Beaury, L.
Hölsä, J.
Korventausta, J.
Krupa, J.-C.
Lamminmäki, R.-J.
Porcher, P.
Rahiala, H.
Säilynoja, E.
Powiązania:
https://bibliotekanauki.pl/articles/1952823.pdf
Data publikacji:
1996-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
71.70.Ch
78.40.-q
78.55.-m
Opis:
The energy level schemes of the neodymium oxyhalides (NdOX, X = F, Cl, and Br) were studied and simulated with a phenomenological model accounting simultaneously for both the free ion interactions and the crystal field effect. The former included the electrostatic and interconfigurational interactions as well as the spin-orbit coupling. The simulations were carried out by using the data from the optical absorption and luminescence as well as the inelastic neutron scattering measured at low temperatures between 2.5 and 77 K. The values of the Slater integral F$\text{}^{2}$ describing the electrostatic interactions decrease while F$\text{}^{4}$ and F$\text{}^{6}$ increase as a function of the ionic radius of the halide anion. The strength of the spin-orbit coupling is quite the same in all three matrices. The crystal field effect - measured as the crystal field strength parameter S - is almost twice as strong in the hexagonal NdOF matrix (650 cm$\text{}^{-1}$) than in the tetragonal NdOCI or NdOBr (367 and 378 cm$\text{}^{-1}$, respectively). Similar evolution was obtained for the short-and mid-range crystal field strengths related to the spatial extension of the interaction.
Źródło:
Acta Physica Polonica A; 1996, 90, 6; 1203-1213
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopic Characterization of Ethylenediamine-di(o-hydroxyphenyl)acetic Acid and its Complexes with Lanthanide(III) Ions
Autorzy:
Hnatejko, Z.
Lis, S.
Elbanowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1945635.pdf
Data publikacji:
1996-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.-m
42.62.Hk
78.40.Ha
78.40.-q
Opis:
Binding properties of ethylenediaminedi(o-hydroxyphenyl)acetic acid (EHPG) with lanthanide(III) ions were studied using spectroscopic methods. Luminescence intensity and lifetime of the Tb(III) ion were measured in a wide pH range in order to characterize the Ln-EHPG complexation. The calculated hydration number of the Tb-EHPG system proved the replacement of six water molecules by the EHPG ligand in the inner coordination sphere of Tb(III). Energy transfer from Tb(III) to Eu(III) in the Tb(III)-EHPG-Eu(III) system indicated an existence of only monomeric form of the Tb-EHPG complex. Analysis of the ^1H NMR and FTIR spectra of the EHPG ligand and its complexes with lanthanide(III) ions confirmed the hexadentate manner of EHPG complexation with the lanthanides. The system of Dy(III)-EHPG, showing a linear dependence of luminescence intensity (λ$\text{}_{em}$=578 nm) of Dy(III) on its concentration, in the range of 3.3×10-7 to 1×10-5 mol. l-1, can be applied for spectrofluorimetric determination of Dy(III).
Źródło:
Acta Physica Polonica A; 1996, 90, 2; 353-359
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopic Studies of Polyoxometalates and their Complexes with Lanthanide(III) Ions in Solution
Autorzy:
Lis, S.
Powiązania:
https://bibliotekanauki.pl/articles/1945607.pdf
Data publikacji:
1996-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.62.Hk
78.40.-q
78.40.Ha
78.55.-m
Opis:
The results of investigations related to physico-chemical properties, synthesis and structure of polyoxometalates and their lanthanide(III) complexes are briefly reviewed. Useful techniques for the verification of polyoxometalate compositions and the determination of components are compared. Complexation of metal ions, especially of lanthanide(III) ions, with polyoxometalates using absorption (in the UV-visible and the near IR region) and luminescence spectroscopy methods are presented. Absorption hypersensitive transitions of certain lanthanide(III) ions and laser-induced europium(III) ion luminescence spectroscopy are shown to be useful in complexation investigations. The significance of some polyoxometalate complexes as potential magnetic resonance imaging agents and in biological studies as antiviral agents are discussed.
Źródło:
Acta Physica Polonica A; 1996, 90, 2; 275-283
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis and Spectroscopic Study of Europium(III) in Heteropolyanion [EuP$\text{}_{5}$W$\text{}_{30}$O$\text{}_{110}$]$\text{}^{12-}$
Autorzy:
Lis, S.
Elbanowski, M.
But, S.
Powiązania:
https://bibliotekanauki.pl/articles/1945636.pdf
Data publikacji:
1996-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.40.Ha
78.40.-q
42.62.Hk
78.55.-m
Opis:
The heteropolyanions of Preyssler anion [NaP$\text{}_{5}$W$\text{}_{30}$O$\text{}_{110}$]$\text{}^{14-}$ and its europium-encrypted derivative [EuP$\text{}_{5}$W$\text{}_{30}$O$\text{}_{110}$]$\text{}^{12-}$ were prepared and spectroscopically characterized. The compositions of these heteropolyanions were verified based on the results from elemental and thermogravimetric analysis and the data of spectrophotometric determination of tungsten contents. Absorption in the UV-vis and IR region and luminescence spectra, as well as results of the laser-induced europium ion luminescence spectroscopy, obtained for solid complexes and their solutions, were analysed. Both in solid and solution the europium-encrypted derivative has three water molecules of hydration.
Źródło:
Acta Physica Polonica A; 1996, 90, 2; 361-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Excited State Absorption and Thermoluminescence in Ce and Mg Doped Yttrium Aluminum Garnet
Autorzy:
Wiśniewski, K.
Koepke, Cz.
Wojtowicz, A. J.
Drozdowski, W.
Grinberg, M.
Kaczmarek, S. M.
Kisielewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/2007834.pdf
Data publikacji:
1999-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Hx
78.55.-m
78.60.Kn
73.50.Gr
29.40.Mc
78.20.-e
78.20.Wc
78.40.-q
Opis:
In this paper we report preliminary results of optical studies on Y$\text{}_{3}$Al$\text{}_{5}$O$\text{}_{12}$ (YAG) crystals codoped with Ce and Mg. By using measurements of luminescence, absorption, and luminescence excitation spectra we demonstrate that although the basic features introduced to the YAG host by the Ce-doping remain intact, the Mg-codoping imposes some significant changes on other properties of the material. These changes are potentially important for laser and/or scintillator applications of YAG:Ce and are due, most likely, to modifications of defect populations in the material. We characterize them by using the techniques of thermoluminescence and excited state absorption under excimer laser pumping. These techniques, interestingly, yield results that seem inconsistent. While the thermoluminescence signal of the Mg-doped sample is strongly reduced, suggesting that trap concentrations in the presence of Mg are suppressed, the excited state absorption signal, which we also relate to the traps, is higher. We offer a tentative explanation of this contradiction between the two experiments that involves a massive transfer of electrons from the Mg-related defects to the excited state absorption centers caused by the excimer pump itself.
Źródło:
Acta Physica Polonica A; 1999, 95, 3; 403-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence and Transient Absorption of CdWO$\text{}_{4}$ Crystals
Autorzy:
Millers, D.
Grigorjeva, L.
Chernov, S.
Powiązania:
https://bibliotekanauki.pl/articles/2010943.pdf
Data publikacji:
1999-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.Ya
78.40.-q
Opis:
Luminescence and transient absorption of the oxygen-deficient CdWO$\text{}_{4}$ crystal were studied. The electron transitions from the excited state of the luminescence center to some higher energy state are responsible for the transient absorption observed. The scheme of luminescence center levels is proposed from the obtained experimental results.
Źródło:
Acta Physica Polonica A; 1999, 95, 6; 965-969
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Model for Luminescence Center Excitation in PbWO_{4}
Autorzy:
Millers, D.
Grigorjeva, L.
Chernov, S.
Pankratov, V.
Powiązania:
https://bibliotekanauki.pl/articles/2010944.pdf
Data publikacji:
1999-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.40.-q
78.60.Ya
61.72.Cc
Opis:
The luminescence and transient absorption of PbWO$\text{}_{4}$ crystals were studied. The electron beam (10 ns, E≈270 keV) was used as excitation source. The kinetics of luminescence is complicated - the prompt rise of luminescence intensity is followed by a slow (τ$\text{}_{r}$≈100 ns) rise. The luminescence decay at 80 K is nearly exponential with τ$\text{}_{d}$≈4.0- 4.5 μs. The decay kinetics of transient absorption at 3.5 eV can be described roughly by two exponents with time constants τ$\text{}_{1}$≈100 ns and τ$\text{}_{2}$≈4.0 μs. A common process responsible for absorption relaxation and luminescence rise is suggested. The luminescence center excitation occurs during recombination process via Pb$\text{}^{2+}$ excited state formation and subsequent energy transfer to WO$\text{}_{4}^{2-}$ group.
Źródło:
Acta Physica Polonica A; 1999, 95, 6; 971-976
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Absorption of Some Glycine Crystals and their Aqueous Solutions
Autorzy:
Koralewski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2035746.pdf
Data publikacji:
2003-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.-e
78.40.-q
Opis:
UV absorption spectra of glycine crystals, i.e. triglycine sulphate, selenate, diglycine sulphate as well as their deuterated analogues in solid state and aqueous solutions are given. Results are compared with the electronic transition energies calculated by LCAO INDO method for glycine molecule and ion, assuming their crystal geometry.
Źródło:
Acta Physica Polonica A; 2003, 103, 5; 459-470
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Characterization of Semiconductor CuCl Nanocrystals
Autorzy:
Mahtout, S.
Belkhir, M. A.
Samah, M.
Powiązania:
https://bibliotekanauki.pl/articles/2037157.pdf
Data publikacji:
2004-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.-n
78.40.Fy
78.40.-q
Opis:
CuCl nanocrystals were elaborated in a NaCl ionic matrix by doping the latter with copper powder during growth. Optical absorption measurements revealed nanocrystals with a mean size of order 32 Å. This is consolidated by the Raman scattering measurements which showed nanodomains of similar size. X-ray diffraction measurements indicate a good crystallinity of the matrix and confirm the presence of CuCl nanocrystals within our samples. The annealing effect at 300˚C showed an increase in CuCl nanocrystal size with annealing time and demonstrated clearly the existence of a compound containing copper within our samples.
Źródło:
Acta Physica Polonica A; 2004, 105, 3; 279-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrafast Phenomena in Freestanding LT-GaAs Devices
Autorzy:
Marso, M.
Mikulics, M.
Adam, R.
Wu, S. Wu.
Zheng, X.
Camara, I.
Siebe, F.
Förster, A.
Güsten, R.
Kordoš, P.
Sobolewski, R.
Powiązania:
https://bibliotekanauki.pl/articles/2041640.pdf
Data publikacji:
2005-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
72.40.+w
78.30.Fs
85.60.-q
85.60.Gz
Opis:
We report on the fabrication and high-frequency performance of our photodetectors and photomixers based on freestanding low-temperature-grown GaAs. The MBE-grown low-temperature GaAs layers are lifted from the native GaAs substrate and transferred on top of variety of host substrates. The freestanding devices exhibit breakdown electrical fields above 200 kV/cm and dark currents below 3×10$\text{}^{-7}$ A at 100 V bias. Device photoresponse shows 0.55 ps wide electrical transients with voltage amplitudes up to 1.3 V, measured using an electro-optical sampling technique with 100 fs wide laser pulses. Photomixing experiments at 460 GHz yield a 9 times higher output power for the freestanding device on Si/SiO$\text{}_{2}$ host substrate compared to the native substrate.
Źródło:
Acta Physica Polonica A; 2005, 107, 1; 109-117
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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