A) S and T PES projection profiles on the imaginary line, connecting the O1, O2, and O3 oxygens of ATP. Solid lines indicate the front PES profiles and dashed line the remote one; b, corresponds to the barrier, separating the T1 and T2 PESs; the cone, c, corresponds to the formation of a spin-separated, ion-radical, state. The S2 and S3 states are considered as metastable, see text. B) 3D topside view of S and T PESs in the configuration space, restricted by r [Mg-(O1-O2-O3)] and O1-O2-O3 coordinates; designations correspond to those in Fig. 3a. The values of r [Mg-(O1-O2-O3)] are as follows: (1) – 2.05 Å; (2) – 2.03 Å; (3) – 1.95 Å; (4) – 2.07 Å; (c) – 1.87 Å.