hi all, can anyone help me understanding what is the meaning of the mixing state of 2p and 2s? thanks in advance. when an electron in n=2 sate in a hydrogen atom, experience a external em field, then the degenerate states split in to 3 classes, which are: 1/sqrt2( 210 + 200 ) with higher energy 2 1 +1 and 2 1 -1 with the same energy as before 1/sqrt( 210 - 200) with lower energy my question is how to interpretate the upper and lower energy states? for upper level, i think it as there is a half probability to find the electron in 210 state and half in 200 state. but if i think in terms of this way, then the lower level becomes half probability in 210 state(which contridicts with it can also in uper level) and -1/2 probability in 200 state( wich is obviously wrong). thanks for any helps.