… To elucidate this issue, we simulated the fluorescence of pyrene using two different
theoretical approaches based on vertical convolution and nonadiabatic dynamics with nuclear
ensembles. To conduct the necessary nonadiabatic … Our VCA and NEA simulations show
that pyrene’s non-Kasha behavior emerges from the dynamic equilibrium between S 1 and S
2 . Pyrene does not get trapped in S 2 . It populates the S 1 minimum, but due to the vibrational
energy excess, it can briefly access S 2 . An example of such behavior is illustrated in Fig. …