Why does Nd_3 has 11 valence electrons while Gd_3 has 9?

[byin]

Dear all,

According to the manual, for the frozen potential RE_3, the number of f-electrons in the core equals the total number of valence electrons minus the formal valency.

For Nd_3, the number of f-electrons in the core = 6-3 =3. So the valence electron number should be 14-3=11. It matches.

For Gd_3, the number of f-electrons in the core = 10-3 =7. So the valence electron number should be 18-7=11. But in Gd_3, it is 9. Why?



By the way, any comments on the choice of pseudopotentials (standard potential or frozen potential) for f-elements in alloy systems would be highly appreciated. Thanks!

Best,
Binglun

[admin]

There is also another variable in the equation.
With increasing electron number the atomic levels
shift deeper. Starting with Eu in the pseudopotential of all
higher elements also 5s2 electrons are frozen in the core.
Therefore for Gd_3 the equation is
18-7-2=9