Theory of Negative Ions in Liquid Helium

A configurational study of helium clusters doped with He∗− and He2∗−

“…The comparison with the results from the other two classical approaches reveals the contribution to the total energy of the zero energy effect. Energies for He 6 -He * − , He 7 -He * − , and He 8 -He * − are quite similar, thus suggesting some sort of saturation when N 6. Present results also indicate the preference of the He atoms to occupy interparticle distances which are driven by the minimum of the He-He potential outside the bipyramid structure.…”

“…The initial kinetic energy of the electron, ∼22 eV, accounts both for the required penetration energy (1.2 eV) 4 and the excitation energy to obtain He * (19.8 eV). Both the resulting zero kinetic energy electron and the excited He * lie in separate bubbles within the helium environment 2,[5][6][7] and finally combine to form He (1s2s2p 4 P) He * − , a fast ion which was initially observed in bulk helium as reported in Ref. 8.…”

“…Present results also indicate the preference of the He atoms to occupy interparticle distances which are driven by the minimum of the He-He potential outside the bipyramid structure. In fact, although the associated errors are clearly larger than the actual differences among these three E PIMC values, one might explain for instance the difference between the E PIMC for He 6 A detailed analysis of the geometry of the clusters has been performed by means of the corresponding density probability functions defined in Eqs. (6)- (8).…”

Studies of homogeneous nucleation and transient heat transfer in cryogenic liquids

“…This was determined by . ----------------------------.,,------------.. -- to as an electron bubble (Ferrel 1951, Sommer 1964, Woolf and Rayfield 1965, Kuper 1961, Jortner et al 1965, Fowler and Dexter 1968, Onn and Silver 1971. The potential for the formation of electron bubbles in liquid helium suggests the possibility of a two-step process in which (1) Further support for the electron bubble hypothesis comes from the suggestion of Hernandez (1970Hernandez ( , 1973) that electrons have a strong tendency to form electron bubbles within regions of spatially localized density fluctuations.…”

Electron mobility and localization in dense He4gas

“…The 'bubble' model of the negative carrier in liquid and dense gaseous helium has been thoroughly studied (Kuper 1959, Jortner er al 1965, Levine and Sanders 1967, Springett et al 1967. In this model an excess electron is pictured as inducing a density variation in the fluid through the repulsive electron-helium atom interaction ; the density variation is often idealized as a void (the bubble) in which the electron can be self-consistently trapped.…”