Exchange Rules for Diradical pi-Conjugated Hydrocarbons
authors Ortiz, R; Boto, RA; Garcia-Martinez, N; Sancho-Garcia, JC; Melle-Franco, M; Fernandez-Rossier, J
nationality International
journal NANO LETTERS
author keywords Nanographene; exchange; zero-mode; symmetry; disjoint; diradical
keywords GRAPHENE NANOFLAKES; GROUND-STATE; CLAR-GOBLET; KEKULE; CHARACTER
abstract A variety of planar pi-conjugated hydrocarbons such as heptauthrene, Clar's goblet and, recently synthesized, triangulene have two electrons occupying two degenerate molecular orbitals. The resulting spin of the interacting ground state is often correctly anticipated as S = 1, extending the application of Hund's rules to these systems, but this is not correct in some instances. Here we provide a set of rules to correctly predict the existence of zero mode states as well as the spin multiplicity of both the ground state and the low-lying excited states, together with their open- or closed-shell nature. This is accomplished using a combination of analytical arguments and configuration interaction calculations with a Hubbard model, both backed by quantum chemistry methods with a larger Gaussian basis set. Our results go beyond the well established Lieb's theorem and Ovchinnikov's rule, as we address the multiplicity and the open-/closed-shell nature of both ground and excited states.
publisher AMER CHEMICAL SOC
issn 1530-6984
year published 2019
volume 19
issue 9
beginning page 5991
ending page 5997
digital object identifier (doi) 10.1021/acs.nanolett.9b01773
web of science category Chemistry, Multidisciplinary; Chemistry, Physical; Nanoscience & Nanotechnology; Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter
subject category Chemistry; Science & Technology - Other Topics; Materials Science; Physics
unique article identifier WOS:000486361900020
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journal analysis (jcr 2017):
journal impact factor 12.080
5 year journal impact factor 14.201
category normalized journal impact factor percentile 91.757
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