Anisotropy and polarization in charge changing collisions of with Na(3s) and laser aligned Na(3p)

Abstract

Absolute cross sections for C 3+ (6→5) emission at 465.7 nm after collisions of C 4+ ions with ground state Na(3s) and laser excited aligned Na(3p) atoms are measured over the collision energy range of 3-7 keV amu −1 . For Na(3s) polarizations are observed by measuring the linear polarization of the emitted light. In these collisions the polarization is found to be 0.33 and almost independent of the collision energy. Cross sections for collisions with the Na(3p) target are up to five times larger than for collisions with Na(3s). Slightly larger cross sections are measured when the laser excited Na(3p) target is -aligned as compared to a -alignment. Classical trajectory Monte Carlo (CTMC) calculations agree excellently with the experimental findings and yield predictions of strong positive polarizations for electron capture also from aligned Na(3p), indicating preferential capture to m = 0 states,.

Polarization degrees of 3p 2P3/2–3s 2S1/2transition in O5+(1s23p) produced in collisions of O6+with He and H2

“…Numerous experiments [4][5][6][7][8][9][10][11][12][13][14][15][16] have been devoted to the determination of photon polarization degrees in charge exchange collisions of ions with atoms and molecules. In the keV energy region, most of these experiments have measured the polarization degrees of light produced in singleelectron capture by highly charged ions from alkali atoms [4][5][6][7][8][9][10][11][12]. The polarization degrees were found to be large, 15 ∼ 40%.…”

“…A number of studies involved charge transfer processes of He-like ions C 4+ , N 5+ and O 6+ with He and H 2 targets [13][14][15][16]. On the theoretical side, the classical trajectory Monte Carlo (CTMC) method has been widely used to calculate the polarization degree of emitted radiation from excited states created in charge transfer processes for the fully and partially stripped ions with alkali atoms [4,11]. Although the agreement between experimental measurements and theoretical calculations in most cases was found to be very good, obtaining the magnetic substate-selective cross sections from the fully classical distributions is an artcraft work.…”

State selective single-electron capture in O6++ Na collisions

“…Experimental work on collisions between alkali atoms and highly charged ions (q 1) to obtain state-selective cross sections has been mainly done by means of photon emission spectroscopy (PES) in which usually only a few (major) capture channels are studied [9][10][11][12][13][14][15][16][17][18]. On the theory side the problem has mainly been addressed by means of classical trajectory Monte Carlo calculations (CTMC) [13][14][15][16][17][18][19][20][21], which do not suffer from basis set size limitations. Close-coupling atomic orbital calculations have only been performed for A q+ -Li (q = 2-6) [22].…”

State propensities in electron transfer processes from optically prepared states:

“…Optically prepared, excited states of atoms have been used extensively in electronic and atomic collision physics, and a wide variety of processes have been studied. In the keV energy range, for heavy-particle collisions involving singly charged ions, in particular the H + − Na(3p) system has served as a prototype (Dowek et al 1990, Roller-Lutz et al 1993 with studies involving doubly (Aumayr et al 1992, Gieler et al 1993a, b, Schlatmann et al 1993, Schippers et al 1993, Aumayr et al 1996 or multiply (Schippers et al 1995(Schippers et al , 1996 charged ions adding valuable information. Recently, theoretical studies have been done by Jain and Winter (1995), Lundy and Olson (1996), Dubois and Hansen (1996) and Fourré and Courbin (1997).…”