  Recent theoretical investigations of pair-production probabilities for given
sets of nuclear trajectories predict the observability of spontaneous positron
emission in elastic collisions of heavy ions. These calculations are extended
to the investigation of ratios $P_{y}(\eta)/P_{y}(1)$ for partial probabilities
of positron emission at small positron energies. The results suggest a possible
observability of spontaneous positron emission in elastic collisions of bare
heavy ions by analyzing the slope of $P_{y}(\eta)/P_{y}(1)$ for values of
$R_{min}$ $~_{\sim}\!\!\!\!^<$ 0.75 $R_{cr}$. In addition calculations of cross
sections for positron emission in U+Cm and Cm+Cm collisions of fully ionized
heavy ions are compared with former results with partly ionized projectiles and
show an increase by factors of 57 to 72.
