Coherent electron beam excitation of a model hydrogen atom
M. S. Pindzola, M. C. Witthoeft, F. Robicheaux
Excitation of a model hydrogen atom by a coherent electron beam is calculated by direct solution of the time-dependent Schrödinger equation on a three-dimensional lattice. The Coulomb interaction between the electrons is described by v ( r 1 , r 2 ) = 1/r > and all angular momenta are set to zero. The coherent beam consists of moving wavepackets for each of two free electrons which arrive at the third bound electron at different times. As recently predicted by Robicheaux and Noordam (2000 Phys. Rev. Lett. 84 3735), the probability for a weak excitation should vary as a function of arrival time. The time-dependent calculations for the model hydrogen atom show that the 1s → 2s excitation probability oscillates about an axis which is between one and two times the excitation probability from only one wavepacket. The frequency of the probability oscillation is found to be equal to the 1s → 2s transition frequency. Large destructive interference of the 1s → 2s cross section is illustrated by contour maps of the 2s projected probability as a function of wavepacket arrival time.
Journal of Physics B Atomic Molecular and Optical Physics•Oct 23, 2000•5 citations