for the description of the singlet manifold, and ESDs with M S = 1 1S i , 2T 1 j , 1T 1 i , 2S j , 1T 0 i , 2T 1 j , 1T 1 i , 2T 0 j for the description of the triplet manifold. After the S 2 matrix is built in the basis of the ESDs with M S = 0 and diagonalized, one obtains two singlet ECSFs (in both compact and expanded notation):