Graphene Nanobelts, Möbius and Higher Order Möbius Strips Formed from Graphene. A Combined CASSCF/DFT Study

• Published in: Russian Journal of Physical Chemistry A 2019-04, Vol.93 (4), p.723-729
• Main Authors: Esau Martinez Olmedo, Serguei Fomine
• Format: Article
• Language: English
• Subjects: Chemistry; Chemistry and Materials Science; Dependence; Electronic structure; Graphene; Ground state; Physical Chemistry; Physical Chemistry of Nanoclusters and Nanomaterials
• ISSN: 0036-0244; 1531-863X
• DOI: 10.1134/S0036024419040216

Twisted graphene nanoribbons with linking numbers ( L k ) of 2 and 3 have been studied at hybrid DFT and CASSCF levels. CASSCF calculations demonstrated strong multireference and polyradicalic character of the ground states in all studied systems. This explains striking discrepancies between DFT and CASSCF results. We demonstrated that taking into account static correlation is important for correct description of the electronic structure of the Möbius strips. CASSCF results show the total spin and the multiconfigurational character of the ground state do not depend on the L k . On the other hand, both DFT and CASSCF show similar trend for dependence of strain energy on the L k . However, CASSCF results indicate higher strain energies for M3- k systems compared DFT. The increase of strain energy is more notable when going from L k = 0 to 1 and from L k = 2 to 3. When going from L k = 1 to 2 the increase in strain energy is notably less.