Cascading photoinduced, elastic, and thermal switching of spin states triggered by a femtosecond laser pulse in an Fe(III) molecular crystal

In this paper we put on solid ground the optical time-resolved study of spin-state photoinduced switching in an Fe(III) compound whose structural dynamics have been recently unveiled. We provide the experimental evidence of complex dynamics, occurring in succession, and spanning ten decades in time. We show that in addition to the ultrafast photoinduced molecular switching occurring on the subpicosecond timescale, there exists two additional switching processes significantly affecting the fate of the macroscopic material: one driven by elastic interactions as volume expansion occurs on a tens of nanoseconds timescale, and another one associated with heat diffusion and thermal switching taking place on a tens of microseconds timescale.