Nuclear particle-hole excitation
= Nuclear particle-hole excitation
Promoting a nucleon from an occupied orbital to an unoccupied orbital creates a particle-hole configuration. Its possible angular momenta come from coupling the particle and hole, and its <parity> relative to the reference configuration is the product of their orbital <parities>. Residual interactions split and mix configurations; a measured nuclear <excitation energy> is not generally just an uncorrected independent-orbital spacing.