Hello, i put a brief report in my web page: http://www.slac.stanford.edu/~azzolini/talks/VIR091104.txt cheers Virginia ----------------------------------------------------------------- .*. Two atoms bump into each other. /V\ One says 'I think I lost an electron!' (/ \) The other asks, 'Are you sure?', ( ) to which the first replies, 'I'm positive.' ^^-^^ -----------------------------------------------------------