Electron Shake Off following theβ−Decay ofHe6

Abstract

The charge spectrum of the ${\mathrm{Li}}^{6}$ ions formed following the ${\ensuremath{\beta}}^{\ensuremath{-}}$ decay of ${\mathrm{He}}^{6}$ has been measured as a function of their recoil energy by means of a specially designed mass spectrometer. The analysis is as follows: charge 1 (89.6\ifmmode\pm\else\textpm\fi{}0.2)%; charge 2 (10.4\ifmmode\pm\else\textpm\fi{}0.2)% of which (0.31\ifmmode\pm\else\textpm\fi{}0.05)% is dependent on recoil energy; charge 3 (0.042\ifmmode\pm\else\textpm\fi{}0.007)% of which (0.024\ifmmode\pm\else\textpm\fi{}0.009)% is dependent on recoil energy. Comparison with theory shows that electron shake off results primarily from excitation by the sudden nonadiabatic change in nuclear charge. An expression is given for describing the simultaneous excitations from the sudden changes in nuclear charge and velocity.