Decay Rate of Energy Eigenfunctions in Classically Energetically Inaccessible Regions in more than One Dimensional Configuration Spaces

An approximate formula is proposed for the decay rate of energy eigenfunctions in classically energetically inaccessible regions in more than one-dimensional configuration spaces. This is achieved by generalizing an approach proposed recently for energy eigenfunctions in the one-dimensional configuration space. The formula is tested numerically in the Pullen--Edmonds model.