Interference of electrons resulting from the photoionization of an atom in an electric field

I. I. Fabrikant

Christian Bordas, F. L�pine, Céline Nicole +1 more

Atomic photoionization provides an experimental situation where the outer electron is ejected to large distance without confinement condition. The application of an electric field during photoionization allows confining the electron flux along one coordinate. Therefore, photoionization in an electric field provides a unique opportunity where quantum properties of the wavefunction are projected into the macroscopic world, permitting a direct view of the square modulus of the electronic wavefunction. We present here the experimental observations of this effect, denominated photoionization microscopy. The analysis is carried out in the framework of the semiclassical model that allows a qualitative interpretation of the experimental results in terms of interferences among various classical trajectories.

Panagiotis Kalaitzis, Sotirios Danakas, F. Lépine +2 more

Synopsis Photoionization microscopy (PM) aims at imaging the flux of slow (meV) electrons released by atomic photoionization in the presence of a static electric field. We discuss the rotation of the linear light polari-zation with respect to the electric field direction. Two-photon ionization out of an m=0 initial state allows for the population of |m|=0,1,2 Stark states. The resulting |m|-beating effects in the PM images are demonstrated theoretically (in hydrogen atom) and experimentally (in Mg atom). Implications on the applicability of tomographic techniques for slow electrons are also discussed.

Daniel I. Khomskii

Sen Zhang, QIU JI-ZHEN, WANG GANG +1 more

The Stark spectrum of Ca atom with m = 0 in the vicinity of n = 10 to n = 13 have been obtained by using two-step excitation and photoionization methods in the applied electric field from 0 to 8 kV/cm. The experimental results show that the 3d2 3P0 and 3d2 3P2 valence states are repelled by n= 12 Stark manifold. The interaction among the zero-field non-degenerate states, valence states and Stark states are discussed. The interference phenomenon, in which valence state and Stark states take part, has been observed. The interference is enhanced when the electric field increase.

James A. R. Samson, Anthony F. Starace