Self-consistent field method effective nuclear charge calculated using

Slater s rules have been used to estimate ionization energies, ionic radii and electronegativities. More accurate effective nuclear charges have been calculated by Clement and Raimondi by using self-consistent field (SCF) methods, and indicate much higher eff values for the d electrons. However, the simplicity of Slater s approach makes this an attractive method for back-of-the-envelope estimations of Zeff. 

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