Fig. 4. (a and b) The emission oscillator strengths of phenanthrene calculated at 1 atm and 2 GPa. (c and d) The overlap function S_r(r) during the S₁ → S₀ transition at 1 atm and 2 GPa (isosurface level = 0.00016 a.u.), the marked regions represent the head-to-head areas between molecules. (e) The contributions of the three parts of the phenanthrene molecule (rings 1, 2, 3) to the hole, electron, and orbital overlap during the S₁ → S₀ transition at 1 atm and 2 GPa.