An arrangement that slightly raises the energy of an electron on atom A relative to atom B gives it a positive mass, while an arrangement that raises the energy of atom B produces a negative electron mass.
22.
Speaking of his discovery at a scientific meeting at Brookhaven National Laboratory on Dec . 8, 1951, Dr . Deutsch explained that positronium is composed of a negative electron and a positive electron that revolve around each other.
23.
"' Negative electron affinities "'can be used in those cases where electron capture requires energy, i . e . when capture can occur only if the impinging electron has a kinetic energy large enough to excite a autodetach after some time.
24.
"Unlike negative electrons, which flash in a stroke of lightning, or flow in a wire as a current of electricity, positrons have an evanescent life measured in millionths of a second, " according to an account of the discovery published in The New York Times the following day.
