In the last example, we calculated the spin ladder of an Fe 4 S 4 cubane cluster and used Stochastic-GAS to understand the role of charge-transfer excitations in differentially stabilizing the low-energy spin-states. We showed that although the current Stochastic-GAS is based on an SD many-body basis, it is possible to efficiently use the method to selectively target pure-spin states of antiferromagnets. A limitation still exists in using the SD-based approach; for some spin states, a relatively slower convergence is observed with respect to the walker number, compared to the spin-adapted implementation. This limitation is independent of the GAS constraints, but depends on the system. This limitation mostly characterizes systems featuring a large number of unpaired electrons, where denser wave functions exist and spin interactions are harder to describe using a SD basis. This limitation is to a large extent removed using spin-adaptation. A spin-adapted Stochastic-GAS strategy is under development and will be presented in a separate work. Via Stochastic-GAS it is demonstrated that the exchange interactions stabilize the high spin states (inverted spinladder for disconnected GAS subspaces with ferromagnetically ordered spin states), while low-spin states are stabilized via charge-transfer excitations, that are included as soon as connected-GAS spaces are considered. For the Fe 4 S 4 cubane system, GAS calculations with single interspace excitations already recover the CAS energy with an error ≤ 1.2 kJ mol -1