Temat: 32 - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Calculation of Coster-Kronig enhancement factors of the some elements in the atomic number range 50 ≤ Z ≤ 59
Autorzy:: Yilmaz, R.
Tematy:: 32.30.Rj
32.50.+d
32.30.-r; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1058825.pdf Link otwiera się w nowym oknie
Opis:: L X-ray fluorescence cross-sections of some elements in the atomic number range 50 ≤ Z ≤ 59 have been calculated theoretically according to subshell excitation energies of elements. The Coster-Kronig transitions (f₁₂, f₂₃, and f₁₃) are non-radiative transitions. The Coster-Kronig enhancement factors due to the effect of the Coster-Kronig transitions on L X-ray fluorescence cross-sections have been calculated theoretically. The calculated values have been compared with other earlier experimental and theoretical values.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 2.

Tytuł:: Transition Rate Dependence on the Non-Zero Initial Momentum in the ADK-Theory
Autorzy:: Ristić, V. M.
Miladinović, T. T.
Radulović, M. M.
Tematy:: 32.80.-t
32.80.Fb
32.80.Rm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2047850.pdf Link otwiera się w nowym oknie
Opis:: Tunneling regime, introduced by Keldysh, in the interaction of strong lasers with atoms has been now accepted as the reliable method for describing processes when low frequency lasers are involved. Yet it was always assumed that the ionized electrons are leaving the atom with zero initial momentum. Because we are interested in how non-zero momentum influences the transition probability of tunnel ionization, we obtained the exact expression for the momentum. Here the estimation of the transition probability with nonzero momentum included was conducted. Potassium atoms in the laser field whose intensity varied from 10$\text{}^{13}$ W/cm$\text{}^{2}$ to 10$\text{}^{14}$ W/cm$\text{}^{2}$ were studied. It seems that all energy of laser field is used for tunneling ionization process at the beginning of laser pulse - ionization probability is large. After that, with further action of laser pulse, ionization probability decreases, probably because part of laser pulse energy is used for increasing momentum of ejected electrons, leaving smaller amounts of light quanta available for ionization of remaining electrons. If laser pulse lasts long enough, then the amounts of light quanta available for ionization become larger, resulting in increase in ionization probability, now with greater starting energy of ejected electrons.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: Calculating Ionization Transition Rate for Circularly Polarized Fields, Including Non-Zero Initial Momentum
Autorzy:: Ristić, V.
Miladinović, T.
Radulović, M.
Tematy:: 32.80.-t
32.80.Fb
32.80.Rm; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1791204.pdf Link otwiera się w nowym oknie
Opis:: Potassium atoms in circularly polarized laser field whose intensity (I) varies from 2× $10^{12}$ W/$cm^2$ to 2.5× $10^{14}$ W/$cm^2$ were studied. In the case when there is zero initial momentum, transition rate (that depends only on I) exhibits standard behaviour: as I increases, so thus the rate, until it reaches its maximum value at 1.1× $10^{14}$ W/$cm^2$; after that, rate diminishes as I increases. In the case of non-zero initial momentum, transition rate (that now depends on I but additionally on initial momentum, too) exhibits following behaviour: dependence of the rate on I follows standard pattern, it rises with increase of I until it reaches its maximum, and then diminishes. But with increase of momentum, ionization rate gradually diminishes.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 4.

Tytuł:: Blackbody-Radiation-Induced Decay and Excitation οf Rydberg States in Sodium
Autorzy:: Ovsiannikov, V.
Glukhov, I.
Tematy:: 32.80.-t
32.80.Ee
32.70.Cs; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1791216.pdf Link otwiera się w nowym oknie
Opis:: Rates of the blackbody radiation-induced excitation and decay were calculated for the S-, P-, D-series of the Rydberg states in sodium atoms with the Fues model potential method. Comparisons between three branches of the state depopulation mechanism (spontaneous decays, blakbody radiation-induced and excitations) were carried out. Simple analytical formulas were proposed for ratios of the blackbody radiation-induced decay and excitation rates to the spontaneous decay rate.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 5.

Tytuł:: NIST Cesium Fountains - Current Status and Future Prospects
Autorzy:: Jefferts, S.
Heavner, T.
Parker, T.
Shirley, J.
Tematy:: 06.20.Fn
32.30.Bv
32.30.-r
32.10.Fn
32.80.Pj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1814049.pdf Link otwiera się w nowym oknie
Opis:: We review the current status of the U.S. Primary Frequency Standard, NIST-F1. NIST-F1 is a laser-cooled cesium fountain based frequency standard with an inaccuracy of less thanδ f/f<5×$10^{-16}$; limited mainly by the radiation field in the room-temperature fountain (blackbody shift). NIST-F1 is one of the best cesium fountains currently contributing to international atomic time, but has reached a point that it is impractical to improve its accuracy substantially. Therefore we are building a new fountain, imaginatively named NIST-F2, with a cryogenic (77 K) Ramsey interrogation zone that lowers the blackbody shift by several orders of magnitude. NIST-F2 is currently undergoing final assembly, and we will discuss our planned (hoped for) performance, which includes frequency inaccuracy ofδ f/f<1×$10^{-16}$.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 6.

Tytuł:: Core Polarization Effects in the Relativistic Quantum-Defect-Orbital Theory
Autorzy:: Bielińska-Wąż, D.
Martin, I.
Karwowski, J.
Tematy:: 32.70.Cs
32.90.+a; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1931291.pdf Link otwiera się w nowym oknie
Opis:: The quantum-defect-orbital method has been reformulated in order to include both relativistic effects and the electron correlation described by a core polarization potential. All quantities appearing in this formulation may be evaluated analytically. A comparison with experimental results demonstrates, on one hand, significance of the relativity-correlation corrections and, on the other, inadequacy of the relativistic quantum-defect-orbital approach when indirect relativistic effects are important, i.e. when atoms contain closed shells of d electrons.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 7.

Tytuł:: Non-Perturbative Dynamics of Atoms in Strong Lrser Fields: Adiabatic Stability of Hydrogen Atom
Autorzy:: Faisal, F. H. M
Dimou, L.
Tematy:: 32.80.Fb
32.80.Wr; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1931518.pdf Link otwiera się w nowym oknie
Opis:: Recent investigations of laser-atom interaction at high intensities have led to the discovery of several unexpected phenomena, and their studies have deepened our understanding of non-perturbative dynamics of quantum systems subjected to unusually strong radiation fields. For the analysis and interpretation of these phenomena. We have developed an ab initio non-perturbative method, the Floquet close-coupling method, and applied it to analyse the highly non-perturbative problem of adiabatic stability of hydrogen atom. Ab initio rates of ionization as a function of the laser intensity for the excited circular states as well as related non-circular states are obtained. Our quantitatively accurate results clearly show that the predictions of the previous approximate theories such as the well-known "high-frequency" theory are qualitatively similar but differ quantitatively. The analysis of the dependence of adiabatic stability on the principal quantum number, the angular momentum, as well as on the magnetic quantum number for the Rydberg states are complemented by investigations of the behavior of the ground state for frequencies below the ionization threshold. In the latter situation we found the existence of stability windows within which the ionization probability decreases with increasing intensity but outside of which the atom becomes more unstable. It is shown here that the mechanism for the occurrence of stability windows is the self-tuned anti-resonance at specific intensities.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 8.

Tytuł:: Photoionization of He - a Field Theoretic Approach
Autorzy:: Bhattacharyya, S.
Mitra, S.
Tematy:: 32.80.Cy
32.80.Fb; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2028891.pdf Link otwiera się w nowym oknie
Opis:: The present paper deals with the field theoretic study of single ionization cross-sectionsσ$\text{}_{ph}$ and σ$\text{}_{C}$ of helium due to photoelectric effect and the Compton scattering, respectively, by photons of energy lying between 0-12 keV. In this energy range,σ$\text{}_{ph}$ gradually decreases with energy whileσ$\text{}_{C}$ gradually increases. There is a crossover point around 6.5 keV where σ$\text{}_{ph}$=σ$\text{}_{C}$=10$\text{}^{-24}$ cm$\text{}^{2}$. Near about this crossover point σ$\text{}_{ph}$ andσ$\text{}_{C}$ curves are like mirror images. The ratio σ$\text{}_{C}$/σ$\text{}_{ph}$ lies between 0.3 to 1.5 in the energy range under consideration. The present results are compared with existing theoretical results.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 9.

Tytuł:: The Emission Spectra for the Cs$\text{}_{2}$NaScCl$\text{}_{6}$:MoCl$\text{}_{6}^{3-}$ System in the Fm3m Space Group
Autorzy:: Acevedo, R.
Meruane, T.
Navarro, G.
Tematy:: 32.70.Fw
32.70.Cs; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2024014.pdf Link otwiera się w nowym oknie
Opis:: On the basis of the data reported by Flint and Paulusz, we have undertaken a theoretical investigation of the intensity mechanism for the various emissions:Γ$\text{}_{8}$($\text{}^{2}$T$\text{}_{2g}$ ) → Γ$\text{}_{8}$($\text{}^{4}$A$\text{}_{2g}$), Γ$\text{}_{8}$($\text{}^{2}$E$\text{}_{g}$), Γ_8($\text{}^{2}$T$\text{}_{1g}$), Γ$\text{}_{6}$($\text{}^{2}$T$\text{}_{1g}$) for the Cs$\text{}_{2}$NaScCl$\text{}_{6}$:MoCl$\text{}_{6}^{3-}$ system in the Fm3m-space group. The experimental data available refer to the visible and near infrared luminescence spectra of MoCl$\text{}_{6}^{3-}$ complex ion in different hosts, such as Cs$\text{}_{2}$NaMCl$\text{}_{6}$ (M = Sc, Y, In), measured between 15,000 cm$\text{}^{-1}$ and 3,000 cm$\text{}^{-1}$ at liquid helium temperatures. At least, five luminescence transitions have been identified and assigned and each of them show extensive vibronic structure. A careful analysis of this experimental data shows that for the various observed electronic transitions, the vibrational frequencies change only slightly, and therefore there is no indication that the system undergoes both a significant and relevant Jahn-Teller distortion (along an active coordinate). There is however clear evidence that for the chloro-elpasolites, there is a strong resonance interaction between ν$\text{}_{3}$(τ$\text{}_{1u}$ : stretching) of the MoX$\text{}_{6}^{3-}$, complex ion and that of the host when M = In, Y. Thus for M = Sc, the slighter higher host ν$\text{}_{3}$, wave number is likely to minimize the effect of this coupling. This evidence will allow us for the Cs$\text{}_{2}$NaScCl$\text{}_{6}$:MoCl$\text{}_{6}^{3-}$ system to neglect, in the first-order approximation, the coupling among the internal and the external vibrations and to proceed using a both a molecular and the independent system models.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 10.

Tytuł:: Fluorescence Spectra Study in Extremely Thin Cs-Vapor Layers
Autorzy:: Vaseva, K.
Todorov, P.
Slavov, D.
Cartaleva, S.
Koynov, K.
Saltiel, S.
Tematy:: 32.30.-r
32.70.Jz; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2047840.pdf Link otwiera się w nowym oknie
Opis:: The high resolution spectroscopy of nanometric-thin alkali-vapor layers was made possible through the development of extremely thin cell. We have investigated the behavior of the extremely thin cell fluorescence spectra both experimentally and theoretically. Experiment is performed on the D$\text{}_{2}$ line of Cs-vapor-layer with thickness L=mλ, where m = 0.5, 0.75, 1, 1.25. For open optical transitions, the fluorescence spectra shows narrow dip on the top of the sub-Doppler-width fluorescence profile, at L≥λ. In case of closed transition, an extremely small feature in the fluorescence slightly shifted from its maximum is observed at L =(5/4)λ. The used theoretical model, based on the optical Bloch equations is in qualitative agreement with the experimental observations.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Informacja

Wyszukujesz frazę "32" wg kryterium: Temat