Constructing Molecular π-Orbital Active Spaces for Multireference Calculations of Conjugated Systems.

ABSTRACT: Molecules with conjugated π systems often feature strong electron correlation and therefore require multireference methods for a reliable computational description. A key prerequisite for the successful application of such methods is the choice of a suitable active space. Herein the automated π-orbital space (PiOS) method for selecting active spaces for multireference calculations of conjugated π systems is presented. This approach allows the construction of small but effective active spaces based on Hückel theory. To demonstrate its performance, π → π* excitations for benzene, octatetraene, and free-base porphine are computed. In addition, this technique can be combined with the automated atomic valence active space method to compute excitations in complex systems with multiple conjugated

SUBMITTER: Sayfutyarova ER 

PROVIDER: S-EPMC6526033 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature