Chemical Physics Letters, Vol.363, No.5-6, 486-491, 2002
Is density functional theory free of spatial symmetry breaking? The case of the linear carbon radical cations: C-3(+), C-5(+), C-7(+), and C-9(+)
Spatial symmetry breaking is examined numerically for the linear C-n(+) (n = 3, 5, 7, 9) radical cations with hybrid 33LYP and local BP86 functionals. B3LYP clearly breaks spatial symmetry for (2)Sigma(u)(+) D-infinityh structures for C-3(+) and C-5(+). BP86 does not break spatial symmetry but generates lower-symmetry lower-energy (2)SigmaC(infinityv) solutions which are not connected with the (2)Sigma(u)(+) D-infinityh structures starting from C-5(+). The (2)Pi(g) and (2)Pi(u). electronic states do not suffer from spatial symmetry breaking. The bent C-3(+), kinked C-5(+), and quasi-linear C-2v and C-2h structures of C-7(+) and C-9(+) are the lowest energy chains. (C) 2002 Elsevier Science B.V. All rights reserved.