Fig. 4. Potential energy functions of the electronic ground state (GS), locally-excited 1ππ* state (LE), and charge-transfer state (CT), with constrained N–H bond distance, for the most stable non-Watson–Crick (non-WC) forms of (A) A·T and (B) G·C, and computed NICS(1)zz values for the equilibrium structures at relevant positions on the potential energy curves (indicated by black circles).
