Oscillations of electron flux in photodetachment of H- in an electric field

Photodetached electron spectrum of H- near a surface having spherical dent

The detached electron flux and photodetachment cross section are derived using the theoretical imaging method and quantum approach for system comprising of hydrogen negative ion ([Formula: see text]) placed near a surface having spherical dent. The dent is modeled like a spherical concave surface. It is observed that the spherical dent generates additional oscillatory and smooth structure in the detached electron flux and photodetachment cross section, respectively. The radius of curvature, inter-ion surface distance and the dent factor strongly manipulate the results. When the inter-ion surface distance is equal to the focal length of the concave surface, the detached electron flux and photodetachment cross section are not well behaved. The photodetachment cross section is also not well behaved for the inter-ion surface distance equal to the radius of curvature. The focus and center of curvature of the concave surface act as a spherical singularity. This study gives new understanding on the photodetachment of negative ions in the vicinity of concave surfaces.

THE INVESTIGATION OF NON-OSCILLATING STRUCTURE OF THE PHOTODETACHMENT CROSS SECTION OF MOLECULAR ANION USING TRADITIONAL THEORETICAL IMAGING METHOD

Using traditional theoretical imaging method, we predict invisible oscillations in the photodetachment cross section of [Formula: see text] near a thin soft surface. A laser which is polarized parallel to the surface is used to knock off electron from [Formula: see text]. Analytical expressions are derived for detached electron flux and photodetachment cross section. The results depend on the inter ion surface distance and separation of the atomic centers of the molecular anion. It is found that the surface strongly affects the detached electron flux and the photodetachment cross section. Unlike the detached electron flux the cross section displays non-oscillating structure. The non-oscillating structure is attributed to the parallel orientation of the laser polarization direction with the thin elastic surface.

Hydrogen atoms under magnification: direct observation of the nodal structure of Stark states

To describe the microscopic properties of matter, quantum mechanics uses wave functions, whose structure and time dependence is governed by the Schrödinger equation. In atoms the charge distributions described by the wave function are rarely observed. The hydrogen atom is unique, since it only has one electron and, in a dc electric field, the Stark Hamiltonian is exactly separable in terms of parabolic coordinates (η, ξ, φ). As a result, the microscopic wave function along the ξ coordinate that exists in the vicinity of the atom, and the projection of the continuum wave function measured at a macroscopic distance, share the same nodal structure. In this Letter, we report photoionization microscopy experiments where this nodal structure is directly observed. The experiments provide a validation of theoretical predictions that have been made over the last three decades.

PHOTODETACHMENT OF ${\rm H}_2^-$ NEAR A SOFT REFLECTING SURFACE

Photodetachment of [Formula: see text] near a soft reflecting surface is investigated by using theoretical imaging method. Analytical expressions are derived for detached electron flux and photodetachment cross section. The surface strongly affects the results and induces oscillation in the detached electron spectra. The photodetachment cross section is double of the H- near a plane wall. For a very large distance between the surface and [Formula: see text](R → ∞) the cross section reduces to the cross section of two center system in free space.

Escape of quantum particles from an open cavity

A negative ion irradiated by a laser provides a coherent source of electrons propagating out from the location of the negative ion. The total escape rates of the electrons when the negative ion is placed inside an open cavity in the shape of a wedge are studied. It is shown that the wedge induces significant oscillations in the total escape rates because of quantum interference effects. In particular, it is shown that, for a wedge with an opening angle of π/N, where N is an arbitrary positive integer, there are (2N-1) induced oscillations in the rates. As a demonstration, the case for a wedge with an opening angle π/5 is calculated and analyzed in detail.