Paramagnetic Excitons in Molecular Crystals

摘要: The possibility of using electron spin resonance to study paramagnetic excited electronic states aromatic crystals is explored. Two limiting cases are considered: On the one hand excitation energy moves from molecule by a diffusion process; on other triplet described Frenkel exciton. In either case intermolecular propagation assumed proceed through virtual ionization states. theory excitons developed in some detail. It shown that there only weak dependence spectra k vector exciton wave, except when near regions band degeneracies. Band degeneracies arise time‐reversal symmetry benzene, naphthalene, and coronene occur boundary planes first Brillouin zone. A Hamiltonian calculated for these three most vectors which far removed degeneracy. Two‐line (with ...