Comparison of Methods for Active Orbital Selection in Multiconfigurational Calculations.

ABSTRACT: Several methods of constructing the active orbital space for multiconfigurational wave functions are compared on typical moderately strongly or strongly correlated ground-state molecules. The relative merits of these methods and problems inherent in multiconfigurational calculations are discussed. Strong correlation in the ground electronic state is found typically in larger conjugated and in antiaromatic systems, transition states which involve bond breaking or formation, and transition metal complexes. Our examples include polyenes, polyacenes, the reactant, product and transition state of the Bergman cyclization, and two transition metal complexes: Hieber's anion [(CO)₃FeNO]^- and ferrocene. For the systems investigated, the simplest and oldest selection method, bas

SUBMITTER: Toth Z 

PROVIDER: S-EPMC7726099 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature