Identifications of Auger spectra from 2-MeV foil-excited carbon ions

Abstract

%'e have measured high-resolution electron decay-in-flight spectra of highly excited carbon ions, produced by 2-MeV C+ beams emerging from carbon foils. An almost complete identification for the resolved spectral lines is suggested for the prompt and time-delayed electron emission spectra. To assign the observed structures excitation energies for various core-excited states have been calculated using the generalized Brillouin theorem -multiconfiguration method of Schwarz and Chang. Experimental term energies for Coulomb and metastable autoionizing states in two-, three-, and four-electron carbon ions are tabulated and compared to calculated transition energies. Because of line blending most of the experimentally deduced term energies are uncertain to + 0.4%. Some spectral features in the high-energy portion of the prompt spectrum can be attributed to decays of doubly excited He-like carbon ions.

Radiative Cascade Repopulation of 1s2s2p 4P States Formed by Single Electron Capture in 2–18 MeV Collisions of C4+ (1s2s 3S) with He

“…In addition, various energy level calculations, Auger yields and line identifications of Auger transitions for Li-like carbon states have also been presented within the field of high resolution Auger projectile spectroscopy in ion-atom collisions by Schneider et al [24,58], Mann [59], Mack and Niehaus [44], and Deveney et al [60]. In all these publications, radiative transitions to the singly excited states 1s 2 nl are only reported.…”

“…Some of the most investigated states in ion-atom collisions are the Li-like doubly excited quartet 1s2snl 4 L states. In particular, the lowest-lying 1s2s2p 4 P state, which is also metastable, has been under study since the early 70s, first observed in the ions of Be + , B 2+ and F 6+ [23], C 3+ [24], O 5+ and F 6+ [25,26], Li [27], as well as in highly charged heavier ions such as Cl 14+ and Ar 15+ [28]. For a general review of optical studies of these states, see also [29] and references therein.…”

The Allure of High Total Angular Momentum Levels in Multiply-Excited Ions

“…Nevertheless, the technique offers another boon: by a simple mechanical shift of the exciter foil, it facilitates the recording of time-resolved spectra and thus the measurement of atomic lifetimes in the nano-to picosecond ranges [14]. Similarly, in the study of Auger electrons (from the autoionization of multiply excited few-electron ions) [15,16], "delayed" spectra (relatively) enhance the decay signal of longer-lived levels [17]. Following the example of S. Mannervik [13] (an article recommended for a review of techniques and problems not covered in the present text), I concentrate my report on photon transitions, many of which compete with Auger decays.…”

Relativistic energy, fine structure, and hyperfine structure of the high-lying core-excited statesP5(n)(n=Gou1, Wang2 2004Phys. Rev. A9000View full textAdd to dashboardCite

“…In the past few decades, the core-excited states of beryllium-like ions have attracted considerable attention to both theoretical [1][2][3][4][5][6][7][8][9][10][11][12] and experimental [13][14][15][16][17][18]. The highlying core-excited quintet state of beryllium-like ions is a complex four-electron atomic system with high orbital, spin, and angular momentum quantum numbers, which can be stable against Coulomb autoionization because of wellknown angular-momentum and parity-selection rules.…”

“…Later, Bruch, Schneider, and collaborators [13][14][15] extended their electron-spectroscopic studies to Be-like boron and carbon. In the calculation of energies and transition rates for some high-lying states of high multiplicities in light atoms and ions, Beck and Nicolaides [2] found the wavelength of the 1s2s2p 2 5 P -1s2p 3 5 S o transition in B + should lie close to 131.0 nm by using the first-order theory of oscillator strengths.…”