I'm a chemist trying to understand atomic term symbol. If we list all the micro-states of certain multi-electron configuration, these micro-states can be grouped into several certain terms characterized by L and S. In other words, when we compute the ML and MS for each of the micro-state, they should belong to certain (L, S) configuration, much analogous to the single electron case where l sets boundary for ml, s for ms. It is legitimate to do so because the operator L and S commute with H, so L and S are good quantum numbers describing the states. After deriving L and S, we use RS coupling scheme to calculate J. If my understanding is correct, then this point should follow: certain micro-state can arbitrarily belong to several terms. For example, 3d2 contains terms 1D and 3P. A micro-state with ML=1, MS=0 can be either 1D or 3P, right? In that sense, it seems pointless talking about specific term of a micro-state, right?