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

Elvira R. Sayfutyarova, Sharon Hammes-Schiffer

Research output: Contribution to journalArticlepeer-review

37 Scopus citations

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 fragments. This combined approach was used to generate two-dimensional potential energy surfaces for multiple electronic states associated with photoinduced electron-coupled double proton transfer in the blue-light-using flavin photoreceptor protein. These types of methods for the automated selection of active space orbitals are important for ensuring consistency and reproducibility of multireference approaches for a wide range of chemical and biological systems.

Original languageEnglish (US)
Pages (from-to)1679-1689
Number of pages11
JournalJournal of Chemical Theory and Computation
Volume15
Issue number3
DOIs
StatePublished - Mar 12 2019
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Computer Science Applications
  • Physical and Theoretical Chemistry

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