“…1 Introduction It has been well known that the lifetimes of molecular excited states and Frenkel excitons are reduced under high-density excitation in aromatic molecular crystals such as anthracene [1,2], pyrene [3], fluoranthene [4], a charge-transfer complex [5], J aggregates [6], and polymers [7][8][9][10][11]. The mechanism of the lifetime shortening is well established to be the Auger process, in which one of two neighboring excitations (excited molecules or Frenkel excitons) are excited to a higher excitation (higher electronic excited state in a molecule or an excited exciton state) and the other to the ground state by the transition dipole-transition dipole interaction [1][2][3][4].…”