Relaxation dynamics of helium nanodroplets after photodissociation of a dopant homonuclear diatomic molecule. The case of Cl2@(4He)N

To investigate the quantum dynamics of the relaxation process of excited helium nanodroplets, He-4(N), arising from the photodissociation of Cl-2 embedded molecules (B <- X electronic transition), here we have performed a time dependent density functional theory (TDDFT) study considering nanodroplets of different sizes (N = 50, 100, 200, 300 and 500), extending a previous study which was centered on the photodissociation step. The relaxation process takes place in the timescale of several hundred picoseconds and a simple dependence of this process on time has been found. The results have been satisfactorily analyzed in terms of a phenomenological model proposed here and also by applying the Rice-Ramsperger-Kassel (RRK) statistical chemical kinetic model for unimolecular reactions. From what we know, this is the first time that the dynamics of these de-excitation processes has been studied, opening up a window for understanding them. We expect that this work will encourage further research on this little known but interesting phenomenon.