In this section we discuss the application of Stochastic-GAS-CI and Stochastic-GASSCF to a stack of five benzene molecules separated by a varying distance, d, ranging from 3.0 Å to 20.0 Å (Figure ). The geometry of the benzene unit was taken from the Computational Chemistry Comparison and Benchmark DataBase. A conventional CASSCF(6, 6) calculation was performed on this structure using OpenMolcas. The resulting MO coefficient matrix was repeated five times along the diagonal to form a block-diagonal coefficient matrix, used as MO basis for the GAS-CI calculations and as starting MOs for the Stochastic-GASSCF optimizations. Since the molecular orbitals of this block-diagonal matrix are not orthonormal, a Gram-Schmidt orthonormalization was performed prior to the stochastic-GASSCF optimization.