منابع مشابه
Excitation Transfer in Helium Afterglow
electronic state because of the relatively large number of other states of He2 lying within kT of the 3p 3IIg • n is interesting to note that the collection of statistically significant data is limited at both high and low pumping intensities. In the former case, the use of an excessively intense correlated source appears to cause progressively shorter lifetimes of the enhanced population as th...
متن کاملEffective Mass of Atom and Excitation Spectrum in Liquid Helium - 4 at T = 0
A self-consistent approach is applied for the calculations within the two-time temperature Green functions formalism in the random phase approximation. The effective mass of 4He atom is computed as m∗ = 1.58m. The excitation spectrum is found to be in a satisfactory agreement with the experiment. The sound velocity is calculated as 230 m/s. The temperature of the Bose-condensation with the effe...
متن کاملEEDF MEASUREMENTS AND EXCITATION PROCESSES IN THE VICINITY OF A HELIUM DISCHARGE CONSTRICTION
Axial distributions of plasma and floating potentials, electron number density and the electron energy distribution function (EEDF) have been measured in the double layer (DL) region of an He discharge constriction. Excitation processes in the constriction region are studied. Using a linearization method for the nonstationary balance equations and choosing appropriate discharge conditions, ...
متن کاملExcitation of autoionizing states of helium-like ions by scattering of high-energy particles
Two-electron excitations of atoms and ions induced by impact of charged particles and photons are fundamental processes, which have been studied since decades. Along with double ionization and ionization accompanied by simultaneous excitation, double excitation is caused by the interelectronic interaction. Accordingly, the cross sections of these processes turn out to be extremely sensitive to ...
متن کاملCollisional excitation of hydrogen and the determination of the primordial helium abundance from H ii regions
This paper investigates the effect of collisional enhancement of the hydrogen lines on the derivation of the helium abundances in low metallicity H ii regions. For this, we have constructed a grid of photoionization models relevant for the analysis of giant H ii regions in blue compact galaxies. We show that the effect of collisional excitation on the Hα/Hβ ratio can be quite important (up to 8...
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ژورنال
عنوان ژورنال: Progress of Theoretical Physics
سال: 1974
ISSN: 0033-068X,1347-4081
DOI: 10.1143/ptp.52.811