Density Functional Theory (DFT) studies on the ground state of NO3((2)A '(2)) radical and the first triplet state of NO3+ cation

Density Functional Theory (DFT) studies on the ground states ((2)A'(2)) Of NO3 radical and on the ground state ((1)A'(1)) and the first triplet state (E-3") Of NO3+ cation provide an unambiguous prediction about their geometr ical structure: the ground states of both NO3 radical and NO3+ cation have D-3h symmetry and the geometrical configuration of the first triplet state E-3" of NO3+ cation has C-2v symmetry. It is shown that as far as the ioniz ation energy calculations on NO3 radical are concerned, the results are onl y slightly different, no mater that gradient corrections of the exchange-co rrelation energy are included during self-consistent iterations or they are included as perturbations after the self-consistent iterations.