Electrons can move through potential barriers by tunneling. Atomic/molecular orbitals are separated by energy differences. Therefore I was wondering if an electron can tunnel from one orbital to another with higher energy, say from a 2s to a 2p, or if it is limited to spatial barriers.
Clarification: It is possible to tunnel to a lower potential (as in scanning tunneling microscopy, that provides a voltage (potential difference)). It is also possible to tunnel to inside the potential barrier (see this question). If at the other side of the barrier there is a state of medium energy (higher than the previous but lower than the barrier), the wavefunction (and therefore the probability of finding the particle) cannot drop immediately to zero, because the wavefunction must be continuous. So, even if by a small probability, the particle must be able to tunnel to another state of higher energy. The question is if this applies only to spatial barriers (as the space between the tip and the sample in STM) or to different states in general, as in atomic orbitals.