"Heisenberg core" in classical-trajectory Monte Carlo calculations of ionization and charge exchange.

Abstract

We present results of classical-trajectory Monte Carlo calculations for bare ions on helium atoms. We impose the Heisenberg uncertainty principle on the classical system and obtain two important benefits. Firstly, the classical He atom is stabilized and thus full four-body classical-trajectory Monte Carlo calculations are possible. Secondly, this excludes from the classical phase space those regions where electron binding energies are below the quantum mechanical ground state. As a result, the range of agreement between calculations and experiment is increased considerably towards higher energies.