MC-PDFT can calculate singlet–triplet splittings of organic diradicals
Abstract
The singlet–triplet splittings of a set of diradical organic molecules are calculated using multiconfiguration pair-density functional theory (MC-PDFT), and the results are compared with those obtained by Kohn-Sham density functional theory (KS-DFT) and complete active space second-order perturbation theory (CASPT2) calculations. We found that MC-PDFT, even with small and systematically defined active spaces, is competitive in accuracy with CASPT2, and it yields results with greater accuracy and precision than Kohn-Sham DFT with the parent functional. MC-PDFT also avoids the challenges associated with spin contamination in KS-DFT. It is also shown that MC-PDFT is much less computationally expensive than CASPT2 when applied to larger active spaces, and this illustrates the promise of this method for larger diradical organic systems.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Feb 13, 2018
- Source ID
- 10.1063/1.5017132
Entities
People
- Donald Truhlar
- Laura Gagliardi
- Samuel J Stoneburner
Organizations
- Air Force Office of Scientific Research
- University of Minnesota