Abstract:
Discusses the optimal choice of the basis for calculations of inner-shell excitations in the collision of heavy ions. Starting from a variational principle which minimises the time-integrated coupling strength, a relation between a model two-centre distance and the actual internuclear separation is derived. For 1s sigma excitations in Pb-Pb collisions it is found that the optimal basis is almost identical to the adiabatic one. For higher quantum states the adiabatic treatment becomes less adequate.