low-Z Atoms Research Articles

Auger rates for soft x-ray transitions in ionic, atomic and metallic lithium

The importance of orbital relaxation in the computation of Auger transition rates for low-Z atoms is demonstrated for atomic Li (1s, 2s2 to 1s2,ks), where relaxation enhances the computed Auger width by a factor of approximately 16. Solid-state effects are estimated to account for at least a factor-of-three additional enhancement for Li metal: Gamma >or approximately=130 meV. Experimental and theoretical implications of these results are discussed.

Anisotropic emission in single crystal sputtering measurements on HCP single crystals

The ejection characteristics of single crystals of zinc, magnesium (hcp) and aluminum (fcc) were determined by bombarding various crystal surfaces with a beam of inert gas ions (Xe/sup +/, Ar/sup +/ and Ne/sup +/). The energy of the bombarding ions varied between 10 and 40 keV. The sputtered particles were collected on cooled, hemicylindrical metal collectors; with the help of an electron probe the thickness of the deposit was measured. Pronounced anisotropic emission was observed in all cases, although random emission comprises the major part of the total ejection. By comparing the (2023) ejection, which is produced by pure surface collisions, and the (1120) ejection, where focusing collisions are involved, it is deduced that surface collisions are mainly responsible for the anisotropic emission. The width of both emission distributions increases linearly to the same extent in the temperature regime between 100 and 370 K. The agreement of the Mg (1120) ejection with the (110) ejection from an aluminum (111) singie crystal is good and thus allows a comparison with the gold (1l0) ejection reported in the literature. The assisted focusing ejection in (0001), which is very pronounced in zinc single crystals and strongly influences the (2023) ejection from the basalmore » plane, does not show up in magnesium. No. (111) ejection occurred in aluminum either. In both cases the weak repulsive potential of the low-Z atoms accounts for the lack of this preferential emission. (auth)« less

Depolarization of Negative Muons in Low-Z Muonic Atoms with Nonzero Nuclear Spin

The decay asymmetries resulting from the residual polarization of negative muons were measured in the components of the ground-state hyperfine doublet of $^{6}\mathrm{Li}$, $^{7}\mathrm{Li}$, $^{9}\mathrm{Be}$, $^{10}\mathrm{B}$, and $^{11}\mathrm{B}$ muonic atoms. The results show a characteristic consequence of the muonmucleus magnetic dipole coupling during the muonic cascade.