Collisional Effects on Induced Emission and Absorption Transition Probabilities in Atomic Systems

1971 ◽  
Vol 26 (3) ◽  
pp. 156-156 ◽  
Author(s):  
Chung-Nan Chang ◽  
Sotiris Koutsoyannis
Keyword(s):  
Transition Probabilities ◽  
Atomic Systems

Quadrupolar Transition Probabilities for Open-Shell Atomic Systems

1993 ◽  
Vol 419 ◽  
pp. 855 ◽  
Author(s):  
T. K. Ghosh ◽  
A. K. Das ◽  
P. K. Mukherjee
Keyword(s):  
Transition Probabilities ◽  
Open Shell ◽  
Atomic Systems

scholarly journals Spectra of a Rydberg Atom in Crossed Electric and Magnetic Fields

Universe ◽  
2020 ◽  
Vol 6 (10) ◽  
pp. 157 ◽  
Author(s):  
Andrei Letunov ◽  
Valery Lisitsa
Keyword(s):  
Magnetic Fields ◽  
Transition Probabilities ◽  
Semiclassical Approximation ◽  
Complex Structure ◽  
Surrounding Medium ◽  
Rydberg Atom ◽  
Spectroscopic Studies ◽  
Matrix Elements ◽  
Atomic Systems ◽  
Electric And Magnetic Fields

Contemporary spectroscopic studies of astrophysical and laboratory plasmas frequently deal with extremely large values of principle quantum numbers of atomic systems. These atomic states are very sensitive to electric and magnetic fields of the surrounding medium. While interpreting the spectra of such excited atomic systems, one faces the problem of a huge array of radiative transitions between highly excited atomic levels. Moreover, external electric and magnetic fields significantly complicate the problem because of the absence of standard selection rules typical for the spherical quantization. The analytical expression in the parabolic representation for dipole matrix elements obtained by Gordon contains hyper-geometric series and it has a very complex structure. The matrix elements that involve the presence of electric and magnetic fields are calculated while using a representation closely related to the parabolic quantization on two different axes. This matrix element depends in a complex way on the transition probabilities in the parabolic coordinate system (Gordon’s formulas) and the Wigner d-functions. This circumstance leads to even greater computational difficulties. A method of simplification of these complicated expressions for transition probabilities is demonstrated. The semiclassical approximation for coordinate matrix elements (Gulayev) and recurrence properties of the Wigner d-functions are used. The Hnβ line is under consideration. Specific calculations for the transition 10–8 in the case of parallel and perpendicular fields are presented.

Transition probabilities of atomic systems between moving walls

1996 ◽  
Vol 54 (4) ◽  
pp. 3480-3488 ◽  
Author(s):  
R. Jáuregui ◽  
C. Villarreal
Keyword(s):  
Transition Probabilities ◽  
Atomic Systems

EELS white line intensities calculated for the 3d and 4d metals

1989 ◽  
Vol 47 ◽  
pp. 388-389
Author(s):  
C. C. Ahn ◽  
D. H. Pearson ◽  
P. Rez ◽  
B. Fultz
Keyword(s):  
Experimental Data ◽  
Line Intensity ◽  
Transition Probabilities ◽  
Initial Increase ◽  
White Line ◽  
Hartree Fock ◽  
Line Intensities ◽  
Integrated Intensity ◽  
X Ray Absorption ◽  
The Continuum

Previous experimental measurements of the total white line intensities from L2,3 energy loss spectra of 3d transition metals reported a linear dependence of the white line intensity on 3d occupancy. These results are inconsistent, however, with behavior inferred from relativistic one electron Dirac-Fock calculations, which show an initial increase followed by a decrease of total white line intensity across the 3d series. This inconsistency with experimental data is especially puzzling in light of work by Thole, et al., which successfully calculates x-ray absorption spectra of the lanthanide M4,5 white lines by employing a less rigorous Hartree-Fock calculation with relativistic corrections based on the work of Cowan. When restricted to transitions allowed by dipole selection rules, the calculated spectra of the lanthanide M4,5 white lines show a decreasing intensity as a function of Z that was consistent with the available experimental data.Here we report the results of Dirac-Fock calculations of the L2,3 white lines of the 3d and 4d elements, and compare the results to the experimental work of Pearson et al. In a previous study, similar calculations helped to account for the non-statistical behavior of L3/L2 ratios of the 3d metals. We assumed that all metals had a single 4s electron. Because these calculations provide absolute transition probabilities, to compare the calculated white line intensities to the experimental data, we normalized the calculated intensities to the intensity of the continuum above the L3 edges. The continuum intensity was obtained by Hartree-Slater calculations, and the normalization factor for the white line intensities was the integrated intensity in an energy window of fixed width and position above the L3 edge of each element.

Sign in / Sign up

Export Citation Format

Share Document