Charge Carrier Generation by Singlet–Singlet Exciton Interaction in Crystalline Anthracene under Weakly Absorbed Light Illumination

A study of double quantum photoconductivity processes due to weakly absorbed light in crystalline anthracene is used to precise the conditions where singlet‐singlet, singlet‐photon, or singlet‐triplet processes are observable. It is found that αss = (6 ± 3) × 10−12 cm3 s−1 and the average singlet photoionization cross section for photons between 4200 and 5000 Å is σsΦ ≦ 2 × 10−19cm2. αss is weakly dependent on T above 200 °K, the corresponding activation energy being (0.03 ± 0.03) eV. Results found in the literature are discussed and in some cases conclusions are corrected.