We recently noticed that Ernstorfer et al. studied the SF mechanism of pentacene crystal using time-resolved ARPES . Their results indicate a CT mediated mechanism with a hybridization of Frenkel and CT states in the lowest bright singlet exciton and support the process proposed from Ref. . However, they can not rule out the mechanism of conical intersection since the interplay of inter/intramolecular vibrations could mediate the population transfer in an ultrafast timescale without the significant structural changes in matter.