Pure electronic, vibronic, and two-particle surface excitons on the anthracene crystal. I. General theoretical basis, experimental study, and analysis of the (0,0) region

Publisher Website
Google Scholar
Abstract
These two papers (papers I and II) present a complete study—theoretical and experimental—of the first singlet–singlet electronic and vibronic transitions of the anthracene crystal. We interpret the new observed structures in terms of pure electronic, vibronic, and two‐particle site shift surface exciton states. The first paper (I) begins by a model description of the bulk and surface excitons in a rigid lattice. We then describe the experimental study of the anthracene crystal reflectivity and surface emission excitation at low temperatures with and without nitrogen coating of the crystal surface. For the first time, we clearly established the following results: (1) The existence and the accurate position of the upper a polarized Davydov component for the pure electronic surface exciton; (2) The equality within our experimental accuracy (≊2 cm−1), of the surface and bulk excitonic Davydov splitting (Δ̄=223 cm−1) and the translational equivalence (δ̄=206 cm−1) of the surface structures with their bulk counterparts; (3) A variation of the surface Davydov splitting when the crystal surface is coated with frozen nitrogen.