Electric Field Gradients of AtomicpElectrons

Calculations from optical spectrums data of the electrostatic field gradient existing at the position of the nucleus in atoms depend on the effective atomic number Z₈. The present article presents a survey of Z₈ values obtained for various elements in varying degrees of ionization. One may conclude from this survey that the relation Z₈=Z-n is a good approximation for calculations dealing with p electrons. On the basis of this relation the average 〈1{r^3}〉 has been evaluated for low-lying states of interest in chemical bonding for atoms having p valence electrons. The results are presented in a graphical form from which the values for the more complicated cases of N, P, As, and Sb are obtained by interpolation. Atomic field gradients obtained in this article are compared with previous estimates in a number of cases of interest.