Rydberg transitions for positron–hydrogen collisions: asymptotic cross section and scaling law

Abstract

The dynamics of 1s → nlm excitations of hydrogen, for arbitrary n, l, m, by positron impact has been investigated using a distorted-wave theory in the momentum space. It has been possible to obtain the distorted-wave scattering amplitude in a closed analytical form. A detailed study has been made on the differential and total cross sections in the energy range 20-300 eV of incident positron. A simple law has been presented for obtaining asymptotic cross sections for excitation into different angular momentum states. To the best of our knowledge, such a study on the differential and total cross sections for 1s → nlm inelastic positron-hydrogen collisions using distorted-wave theory is the first reported in the literature.

Positron impact excitations of hydrogen atom embedded in dense quantum plasmas: Formation of Rydberg atoms

“…The enhancement of the total cross section is exhibited not only in the 1 s -np transitions, but for any "optically allowed" (dipole) transitions, as we discussed in earlier work. 40 Numerical results of the excitation cross section for various screening effects are presented in Table IV for the sake further investigations in this field. It is worthy to be mentioned here that in vacuum cross sections for excitation to different angular momentum states can be estimated by using the scaling law 40…”

“…2 p transitions, except a few. [40][41][42][43][44] Because, in general, carrying out a sophisticated quantum mechanical calculation involving highly excited states is complicated in practise due to the presence of a large number of oscillations in the final bound state wave function. In presence of plasma medium, calculations get further complicated due to the lack of knowledge of the exact hydrogenic wave function in plasma.…”

Regularity and Chaos in the Hydrogen Atom Highly Excited with a Strong Magnetic Field

“…A lot of works have been recently dedicated to the study of two-or multilevel systems such as Rydberg atom, excitonic systems, and nanoresonators [1][2][3][4][5][6][7][8][9][10][11][12][13]. Its great importance lies in its implication in different branches of physics: astrophysics [9,12], atomic physics [14][15][16][17], molecular physics [18,19], spectroscopy [20,21], solid state [22], and plasma physics [23]. It leads to interesting quantum features such as soliton propagation [24][25][26][27][28][29][30], entanglement [31,32], antibunching [33], squeezing [34], bistability [35], and chaos [36,37].…”