J. Murray-Krezan and R.R. Jones
Approximate momentum distributions of Rydberg electrons in static electric fields have been obtained using an improved Impulsive Momentum Retrieval (IMR) technique. An imaging detector enables the measurement of HCP ionization probability across the spatial profile of a focused half-cycle pulse beam. By modulating the HCP amplitude we directly measure the derivative of the ionization vs. HCP impulse curve, enabling the recovery of momentum distributions with finer resolution than previously attainable. For example, for Stark states with nearly zero dipole moments, we observe a notch in the projection of the momentum distribution along the Stark field axis. We have developed a semi-classical method for simulating the effect that the finite HCP duration has on our measurements. Good agreement between simulated and measured momentum distributions is obtained.
Status: Physical Review A 75, 063411 (2007).
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