Dynamics of Excess Electron Localization in Liquid Helium and Neon

Abstract

In this paper, we address the relations between the structure, electronic level structure, energetics, and localization dynamics of an excess electron in a bubble in liquid 4 He, 3 He, and Ne. Our treatment of the dynamics of formation for the electron bubble rests on a quantum mechanical Wigner-Seitz description of the excess electron in conjunction with a hydrodynamic picture for the liquid. The dynamics of electron localization is described in terms of the initial formation of an incipient bubble of radius 3.3-3.5 Å followed by adiabatic bubble expansion in the ground electronic state. The hydrodynamic model for bubble expansion considers the expansion of a spherical cavity in an incompressible liquid with the energy dissipation being due to the emission of sound waves. This model predicts the bubble expansion time (τ b D ) in liquid 4 He to be τ b D ) 8.5 ps at P ) 0, exhibiting a marked pressure dependence (decreasing by a numerical factor of 4 at P ) 16 atm) and revealing a small isotope effect of τ b D ( 4 He)/τ b D ( 3 He) ) 0.83 in liquid 3 He, while for liquid Ne, τ b D

Photoelectron Imaging of Helium Droplets Doped with Xe and Kr Atoms

“…V 0 has been well-established both experimentally 45,47,48 and theoretically. [68][69][70] It represents a barrier to injection of free electrons into bulk liquid He as well as the minimum kinetic energy that a free electron can have in the liquid before localization to a bubble state occurs. 16 Electron scattering experiments on He droplets have also shown evidence for a barrier to electron injection and/or attachment.…”

Atomic and molecular defects in solid 4He

“…The further development of the electron bubble model [27][28][29] included a refined description of the surface tension and the volume kinetic energy, as well as the polarization of He atoms by the embedded electron that gives an additional contribution V pol (r,R) to the energy of the defect. More recently a hydrodynamic model [30,31] was presented that treats the dynamics of the electron bubble formation in liquid He. The results of numeric calculations [32,33] using the density functional technique are in good agreement with those of the bubble model.…”

Photostimulated electron detrapping and the two-state model for electron transport in nonpolar liquids

“…suggesting even longer times). 108 The model of Rosenblit and Jortner 65 gives ca. 8-10 ps expansion times for the spherical cavity during its thermalization.…”