Electrons in the atom tend to be as close as possible to the nucleus in a position in the shells that is not yet occupied. Photons are emitted during the transitions to deeper states (relaxation).
The ground state of the electron is disturbed by the absorption of photons. The electron enters an excited state under the absorption of photons.
<aside> 📌 Presumtion: The electron absorbs photons until the transition to an unbounded electron. The electron emits photons on its way to the ground state. ↓7↓
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TL;DR Inneratomic reduction of elementary electric fields