 Also, by expressing the fourth-order correction in the Taylor expansion above as ("aCvZ"0) / (Z4), where "a" is some constant, we can define "Z"0 as the position of the "dynamical image plane" and obtain

The origin of "Z"0 comes from the spilling of the electron wavefunction out of the surface.As a result, the position of image plane representing the reference for the space coordinate is different from the substrate surface itself and modified by "Z"0.Table 1 shows the jellium model calculation for van der Waals constant "Cv" and dynamical image plane "Z"0 of rare gas atoms on various metal surfaces.