Fig. 3

Contributions of orbital replacements and spin density comparison. a The electron density change between ground and excited state arises from a linear combination of orbital replacements with CT (blue arrows) and LE (black arrows) character. The HOSO to LUSO transition which contributes strongest (64%), has CR character, moving the α-electron from left to right and the β-electron from right to left. This leads to a partial ¹TT character of S₁. b α-HOSOs of 2P-PDPP and 2P-TDPP (the symmetry equivalent β-orbitals are omitted). In 2P-PDPP α- and β-electrons are spatially separated because the SOs are polarized towards opposite pentacenes. In 2P-TDPP the SOs of α-and β-electrons are less polarized and involve the bridge more strongly