Fig. 2: Reaction pathways for the benzyl radical self-reaction.

This reaction leads to phenanthrene (p1) calculated at the CBS-QB3 level theory as extracted from Ref. 14. Novel reaction pathways to anthracene (p2) computed at the G3(MP2,CC)//B3LYP/6-311G(d,p) level of theory in the present work on the singlet and triplet surfaces are color coded in blue and red, respectively. All energies are presented in the unit of kJ mol−1. Carbon and hydrogen atoms are color coded in gray and white, respectively. Cartesian coordinates and vibrational frequencies are provided in Supplementary Table 1.