The Singly-Ionized Charge State

As for Mg°, no even-parity transition is detected in the Mg+ spectrum, but the Fano resonances involving the 2s (Ai) and 2s (T2) transitions allow determination of the position of these two levels [130]. This high-resolution 

An EM spectrum attributed to the singly-ionized state of a (Mg,0) complex has been observed in O-containing B-doped silicon diffused with Mg at higher energy than the Mg+ spectrum, and the ionization energy of this centre is 274.90 meV [102]. This seems to show that the (Mg,0) complex is a double donor. 

This attribution is confirmed by the observation of an expected isotope component (unresolved) of the 1T7 line in a silicon sample doped with sulphur enriched with isotope 33S [206]. The isotope shifts observed for 1T7 and ir8 with respect to the strongest component, noted 0 in Fig. 6.18, are given in Table 6.17. 

The 1T7 and ir8 ls(T2) lines of S+ have recently been observed at 1.5K in qmi 28Si at a resolution of 0.3 peV (0.0024 cm-1) by Steger et al. [233], The isotopic effect due to silicon is absent as well as the broadening of the lines due to isotopic randomness existing in natSi. The FWHMs of 1T7 and ir8 observed for 34S are 1.0 and 2.7peV, respectively (0.008 and 0.022 cm-1), compared to 22 and 30 peV in natSi at 6 K in Fig. 6.18. A FWHM of 1 peV is presently the smallest one ever reported for an electronic impurity absorption line in silicon and probably in any bulk semiconductor. The FWHMs reported 

The same value of +35peV is obtained for the 33S shift of line r7 either by linear interpolation between the 32 S and 34 S values or by direct measurement in a sample enriched with 33S. The last row is an estimation of the shifts of the components denoted by arrows in Fig. 6.18 [206]. For the positions of 0(r7) and 0(rs), see Table6.18 

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When the same measurements as those of Fig. 6.32 are repeated at 34 K with sample (a), the only contribution observed is that of the singly-ionized charge states at higher energies, with metastability. A noticeable difference, however, is that if full metastability is observed for the D+ and E+ lines, no equivalent of the F ° line is detected in any spectrum. It has been suggested that despite the fact that no ESR signal can be related with TD1, the F ° spectrum could be due to S = 1 configuration [48]. 

We have extended the technique of Relaxation Spectrum Analysis to cover the seven orders of magnitude of the experimentally available frequency range. This frequency range is required for a complete description of the equivalent circuit for our CdSe-polysulfide electrolyte cells. The fastest relaxing capacitive element is due to the fully ionized donor states. On the basis of their potential dependence exhibited in the cell data and their indicated absence in the preliminary measurements of the Au Schottky barriers on CdSe single crystals, the slower relaxing capacitive elements are tentatively associated with charge accumulation at the solid-liquid interface. 

For example, say we wish to discuss the single ionization of helium by a fast proton. In the Born approximation we need a description of the initial and final state. For the initial state clearly the ground state Hartree-Fock field is most appropriate. As we are dealing with a closed shell the Hartree-Fock field is neutral at large distances for continuum states. The final continuum state might leave one electron in the ground state of the helium ion. An appropriate potential for the latter electron is a Coulombic field of charge two. 

The conventional spectrosct k notation fcx- zero-valent actinium is Ac L Similarly, the singly ionized species is Ac II, and the doubly charged, Ac ID. The chemkal notation for the latter is Ac Ac(u). I en referring to free-ion spectra we will use the spectroscopic notation. When indicating the valence state of an ionic species in a condensed phase we will use the chemical notation. We use the symbol An to represent any actinide element, Ln as the general symbol for the lanthanides. 

Figure 14. Double differential cross sections (ddcs — 2n dv v J for electron emission due to single, double, or triple ionization of Ar by 3.6-MeV/amu Au53+ ions. The DDCS for the specified recoil-ion charge states are added according to their relative contribution to the total cross section. CDW-EIS results (solid lines [73]) are shown along with the experimental data from Moshammer et at. [53], The experimental data are divided by 1.4. Cross sections at different ve are multiplied by factors of 10, respectively.

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