On the longitudinal momentum of the electron at the tunneling exit

Abstract

The longitudinal momentum of the electron at the tunneling exit is a useful quantity to make sense of the tunneling ionization process. It was usually assumed to be zero from a classical argument, but recent experiments show that it must be nonzero in order to explain the measured electron momentum distributions. In this article we show that the flow momentum of the probability fluid is a sensible quantum mechanical definition for tunneling-exit momentum, and it can be (and in general is) nonzero at the tunneling exit point where the kinetic energy is zero by definition. We show that this longitudinal momentum is nonzero even in the static or adiabatic limit, and this nonzero momentum is a purely quantum mechanical effect determined by the shape of the wave function in the vicinity of the tunneling exit point. Nonadiabaticity or finite wavelength may increase this momentum substantially, and the detailed value depends on both the atomic and the laser parameters.

References in corpus (5)

• Experimental evidence for Wigner's tunneling time
• Classical collisional trajectories as the source of strong-field double ionization of helium in the knee regime
• Ionization Time and Exit Momentum in Strong-Field Tunnel Ionization
• Tunneling dynamics in multiphoton ionization and attoclock calibration
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Cited by in corpus (8)

• Photoelectron holographic interferometry to probe the longitudinal momentum offset at the tunnel exit
• Recollision induced nuclear excitation of ${}^{229}$Th
• On the quantum tunneling time: Instantaneous, finite or probabilistic?
• Nondipole effects in tunneling ionization by intense laser pulses
• Quantum interference in strong-field ionization by a linearly polarized laser pulse, and its relevance to tunnel exit time and momentum
• Experimental fingerprint of the electron's longitudinal momentum at the tunnel exit in strong field ionization
• Extended virtual detector theory including quantum interferences
• On numerical solutions of the time-dependent Schrödinger equation