Atomic electron transitions are not typically considered as quantum tunneling phenomena. Quantum tunneling refers to the phenomenon where a particle can pass through a potential energy barrier that would be classically forbidden.
In the context of atomic electron transitions, the transitions occur when an electron moves between different energy levels within an atom. These transitions are governed by the laws of quantum mechanics and involve the emission or absorption of photons. However, they do not involve the electron tunneling through a potential barrier.
Instead, atomic electron transitions are typically described using principles such as energy conservation and the quantization of energy levels in the atom. The transitions occur when the electron absorbs or emits energy in discrete amounts corresponding to the energy difference between the initial and final states.
Quantum tunneling is more commonly associated with phenomena such as alpha decay, where an alpha particle can tunnel through the potential barrier created by the nuclear forces. It is also observed in devices such as scanning tunneling microscopes (STMs), where electrons can tunnel through a thin insulating barrier between a conducting tip and a sample.
So, while atomic electron transitions are quantum mechanical processes, they are not considered as examples of quantum tunneling.