<Ul> <Li> Quantum - mechanical coupling </Li> <Li> Ro--vibrational spectroscopy </Li> <Li> Vibronic coupling </Li> <Li> Rovibronic coupling </Li> <Li> Angular momentum coupling </Li> <Li> NMR coupling or J - coupling </Li> </Ul> <Li> Quantum - mechanical coupling </Li> <Li> Ro--vibrational spectroscopy </Li> <Li> Angular momentum coupling </Li>

State the selection rules for allowed transitions in multielectrons atoms