Popis: |
The nonplanar structure of the electronic ground state of 5,10 dihydrophenazine (PH2) is responsible for a distribution of sites of PH2 observed upon doping into molecular crystals. The change in molecular geometry of PH2 following optical excitation results in considerable stress at the respective crystalline site, which is compensated by guest reorientation. Photochemical hole burning experiments suggest that this reorientation involves the 118 cm−1 butterfly backbone vibration of PH2 as indicated by a hole width equivalent to a vibrational relaxation time of 600 fs. |