For a one-hole-one-particle state we have $$ |^{16}\mathrm{O}\rangle_{1p1h} =|(ai)M\rangle = a_a^{\dagger}a_i|^{16}\mathrm{O}\rangle=|\Phi_{i}^a\rangle, $$ and finally for a two-particle-two-hole state we $$ |^{16}\mathrm{O}\rangle_{2p2h} =|(abij)M\rangle = a_a^{\dagger}a_b^{\dagger}a_ja_i|^{16}\mathrm{O}\rangle=|\Phi_{ij}^{ab}\rangle. $$