Program version: Qchem 5.2 I have tried changing the SCF settings for a large close shell system (F1: 363 atoms ; F2: 71 atoms) with the following options and combinations to solve this EDA 2: SCF_ALGORITHM GDM and DIIS_GDM THRESH 14 FRGM_METHOD STOLL and GIA UNRESTRICTED TRUE and FALSE max_scf_cycles from 300 to 1000 Nothing seems to converge and i do not have more ideas.…