DC strong field stark effect for nonhydrogenic atoms: Consistent quantum mechanical approach

Abstract

of resonances extending into the ionization continuum. Unique characteristics in a photoionization spectrum are connected to the presence of a nonhydrogenic core, which produces the interference dips below threshold and attenuates the modulations above threshold. Although the known semiempirical approach of Harmin (cf. [4]) is quite effective, a fully adequate and consistent theory of this phenomenon has been lacking.Calculation of the characteristics of atom in a strong electric field remains a very important problem of modern quantum physics [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. As is well known, the external electric field shifts and broadens bound state atomic levels. The standard quantum mechanical approach relates complex eigenenergies (EE) E ϭ E r ϩ0.5iG and complex eigenfunctions (EF) to the shape resonances. The calculation difficulties in the standard quantum mechanical approach are well known. The WentzelKramers-Brillouin (WKB) approximation overcomes these difficulties for the states, lying far from "new continuum" boundary and, as rule, is applied in the case of a relatively weak electric field. The same is true with regard to the widespread asympCorrespondence to:

SENSING THE OPTIMAL PLASMA PARAMETERS FOR X-RAY LASING: CALCULATION OF ELECTRON-COLLISION STRENGTHS FOR Ar-LIKE PLASMA

“…The key momet of present calculation is the using the Debye shielding approximation. It is a main difference from the analogous calculation for Ne-like [11][12][13] and Ar-like [17] ions. Recent advances in ultra-short laser technologies have shown laser plasmas tyo be a favourable source of quantum emission.…”

“…The properties of laser-produced hot and dense plasmas, known as laser plasma, have drawn considerable attention ove the last two decades through the recent laser-fusion studies [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Similar interest is also stimulated by importance of this information for correct determination of the characteristics for plasma in thermonuclear (tokamak) reactors, searching new mediums for X-ray range lasers.…”

“…In ref. [10][11][12][13][14] two new consistent relativistic and QED versions for calculations of the spectroscopic characteristics of the multicharged ions in plasma have been developed. Ih this paper we use them for sensing and diagnostics of the laser plasma parameters, i.e.…”

“…Let us present the key moments of the new consistent perturbation theory (PT) version for calculation of the electron collision strengths and rate coefficients of electron-collisional excitation for ions in a plasma [12][13][14]. It bases on the gauge invariant QED energy approach to construsction of the relativictic functions basis s [15,16] and using the Green s function method for accounting of the complex exchange-correlation, radiation and others corrections.…”

“…Below we first use such a basis in calculation of the electron-collision cross-sections and strengths. Further we briefly discuss the energy approach in scattering theory 11,12] and give main formulas. We briefly outline the main idea using, as an example, the collisional de-excitation of the Ar-like ion: (F o ,e sc ).…”