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The effective atomic number Z eff, (sometimes referred to as the effective nuclear charge) of an electron in a multi-electron atom is the number of protons that this electron effectively 'sees' due to screening by inner-shell electrons. It is a measure of the electrostatic interaction between the negatively charged electrons and positively ...
An example provided in Slater's original paper is for the iron atom which has nuclear charge 26 and electronic configuration 1s 2 2s 2 2p 6 3s 2 3p 6 3d 6 4s 2. The screening constant, and subsequently the shielded (or effective) nuclear charge for each electron is deduced as: [ 1 ]
The shielding effect can be defined as a reduction in the effective nuclear charge on the electron cloud, due to a difference in the attraction forces on the electrons in the atom. It is a special case of electric-field screening. This effect also has some significance in many projects in material sciences.
However, electrons of multi-electron atoms do not experience the entire nuclear charge due to shielding effects from the other electrons. In this case, the nuclear charge of atoms that experience this shielding is referred to as effective nuclear charge. Shielding increases as the number of an atom's inner shells increases. So from left-to ...
The effective atomic number for electron interactions may be calculated with a similar approach. [5] [6] The cross-section based approach for determining Z eff is obviously much more complicated than the simple power-law approach described above, and this is why freely-available software has been developed for such calculations. [7]
The atomic core has a positive electric charge called the core charge and is the effective nuclear charge experienced by an outer shell electron. In other words, core charge is an expression of the attractive force experienced by the valence electrons to the core of an atom which takes into account the shielding effect of core electrons.
is a constant related to the effective charge of the nucleus, the nuclear charge being partly shielded by electrons. Historically, the effective nuclear charge was estimated by Slater's rules. The normalization constant is computed from the integral =!
As the nuclear charge of the nucleus increases across the period, the electrostatic attraction increases between electrons and protons, hence the atomic radius decreases, and the electron cloud comes closer to the nucleus [10] because the electrons, especially the outermost one, are held more tightly by the higher effective nuclear charge.