Figure 2.

Supercell and Energy Diagram of all Spin States for Hexacene Single Crystal

(A) 9 × 9 × 3 supercell of a hexacene single crystal. The tetramer designated as the singlet fission reaction center is highlighted. The molecular pair along the crystal a axis is colored blue, whereas the one along the crystal b axis is colored red. Moreover, all nearest neighbors of the tetramer are colored green.

(B) Energy diagram of all spin states participating in the single-fission process. The ground state, singlet excited state, charge-transfer state, correlated triplet pair, and uncorrelated triplet dimer are denoted as S₀S₀, S₁S₀, CT, ¹(T₁T₁), and T₁ + T₁, respectively. Their subscripts of a and b refer to the corresponding crystal axes. For instance, ¹(T_1aT_1a) represents a correlated triple pair whose constituents are along the [100] crystal axis.