HOMO and LUMO are acronyms for Highest Occupied Molecular Orbital and Lowest Unoccupied Molecular Orbital respectively. The energy level difference of the two (HOMO-LUMO) can (sometimes) serve as a measure of the excitability of the molecule: the smaller the energy, the easier it will be excited.
See also Diels-Alder reaction, Electron configuration
Last updated: 08-23-2005 16:31:47