I'm trying to decipher exactly what it means to say the following things: (1) The ground electronic state of NO[itex]_2[/itex] is [itex]^{2}A_1[/itex]; (2) The ground electronic state of ClO[itex]_2[/itex] is [itex]^{2}B_1[/itex]; (3) The ground electronic state of O[itex]_2[/itex] is [itex]^{3}\Sigma^{-}_g[/itex]. I really don't have a clue what these symbols are supposed to mean. Can someone please help?