Decay rates of planar helium

in Europhysics Letters [=EPL] (2005), 70(2), 183-189

We compare the autoionization rates of characteristic configurations of the doubly excited helium atom, in one, two and three dimensions. We find that the decay rates of the two-dimensional restriction ... [more ▼]

We compare the autoionization rates of characteristic configurations of the doubly excited helium atom, in one, two and three dimensions. We find that the decay rates of the two-dimensional restriction are in quantitative agreement with those of the real physical system, whilst the one-dimensional model can underestimate the actual decay rates by orders of magnitude. [less ▲]

Algebraic decay of the survival probability in chaotic helium

in Physical Review. A (2001), 63(2), 024701

We demonstrate that the classical helium atom exhibits algebraic decay of the survival probability in the autoionizing eZe configuration. Excitation towards asymptotic orbits of marginal stability is ... [more ▼]

We demonstrate that the classical helium atom exhibits algebraic decay of the survival probability in the autoionizing eZe configuration. Excitation towards asymptotic orbits of marginal stability is identified as the cause of the nonexponential decay. Since one electron travels along a bound Kepler trajectory of infinite excitation in these orbits, we argue that the classical decay law will prevail in the quantum dynamics of a wave packet launched along the eZe configuration. [less ▲]

Nondispersive two-electron wave packets in the collinear driven helium atom

in Europhysics Letters [=EPL] (1999), 46(1), 24-30

Nondispersive two-electron wave packets are found in the Floquet spectrum of the driven, one-dimensional helium atom. In classical phase space, they are anchored to the principal nonlinear resonance ... [more ▼]

Nondispersive two-electron wave packets are found in the Floquet spectrum of the driven, one-dimensional helium atom. In classical phase space, they are anchored to the principal nonlinear resonance between the collinear frozen planet orbit and the driving field linearly polarized along the orbit. These novel, highly correlated eigenstates of the driven three-body Coulomb problem, exhibit lifetimes of the order of 10(3)...10(7) periods of the driving field, with strong fluctuations reminiscent of chaos-assisted tunneling. [less ▲]

Classical support for non-dispersive two electron wave packets in the driven helium atom

in Journal of Physics : B Atomic Molecular & Optical Physics (1998), 31(11), 489-495

We present numerical evidence for the existence of a classically non-ionizing, highly correlated two-electron configuration which emerges from the frozen planet configuration of helium exposed to an ... [more ▼]

We present numerical evidence for the existence of a classically non-ionizing, highly correlated two-electron configuration which emerges from the frozen planet configuration of helium exposed to an electromagnetic field of linear polarization. A static electric field parallel to the polarization axis prevents this configuration from transverse ionization. We argue that the corresponding nonlinear resonance island in 12D phase space supports nondispersive wave packets of the helium atom in combined oscillating and static electric fields. [less ▲]