In the latter case the diamagnetic contribution from the closed shell inner electrons simply wins from the weak paramagnetic term of the almost free electrons.
Instead of beta-plus emission, an inner atomic electron is captured by a proton in the nucleus.
Following removal of an inner electron by an energetic photon provided by a primary radiation source, an electron from an outer shell drops into its place.
In order to excite the atoms, a source of radiation is required, with sufficient energy to expel tightly held inner electrons.
The team used ultra-intense X-rays to knock the inner electrons out of a single atom, creating a "hollow" atom.
X-ray: electromagnetic radiation caused by deflection of electrons from their original paths, or inner orbital electrons that change their orbital levels around the atomic nucleus.
An outer shell electron will eventually transition to fill the missing inner electron thereby droping to a lower ground state.
"It is so heavily charged in the nucleus that its X-ray spectrum is well toward the gammal The inner electrons can scarcely vibrate."
Replies: The atomic radius is a balance between atomic number, the orbital of the valence electron(s), and the shielding of inner electrons.
So, even the outer electrons shield the inner electrons from the nuclear charge, to some extent.