# Nomenclature of Electronic states

We often see electronic states are named like nπ* or ππ* states. What is the reason behind this kind of naming ?

• Hello and welcome to Chemistry.SE! At this point I suggest that you take the short tour of the site. Best of luck... – airhuff Feb 19 '17 at 4:35
• Can you give specific examples? I'm not sure what your question is. – Avishai Barnoy Feb 19 '17 at 6:38
• Are you sure you are not looking at the labels of electronic transitions? For example $\mathrm{n-\pi^*}$ would be the the transition of an electron from a nonbonding orbital to a $\pi$ antibonding orbital. – Ben Norris Feb 19 '17 at 11:27
• As @Ben Norris writes the $\pi\pi^*$ refer to electronic transitions between states. The notation is just a simplification/shorthand to indicate the type of molecular orbitals the HOMO /LUMO electrons are in, rather than using proper symmetry labels. – porphyrin Feb 19 '17 at 11:59