Figure 1
From: Exciton Relaxation Cascade in two-dimensional Transition Metal Dichalcogenides

Intra-excitonic relaxation cascade in MoSe2. A pump pulse with an energy close to the single-particle band gap excites quasi-free electron-hole pairs at the scattering continuum (yellow arrow). The hot electron-hole pairs dissipate energy via a sequence of phonon emissions, performing a cascade-like relaxation through energetically lower lying exciton states (orange arrows) including indirect KΛ excitons.