A characteristic molecular contour evaluated by a theoretical method

The potential Vα(r1) acting on an α-spin electron at position r1 in a molecule is expressed and then calculated using an ab initio quantum chemical program. An intrinsic characteristic contour of a molecule is defined by those points R where the equation Vα(R)=−I is observed, in which I is the first ionization potential of the molecule. This implies that the molecular contour represents the classical turning surface for the electronic motion within the molecule. A few examples are shown and discussed.