Spin- and phase transition in the spin crossover complex [Fe(ptz)6](BF4)2 studied by nuclear inelastic scattering of synchrotron radiation and by DFT calculations

Starting at the ordered high-spin phase (a) fast cooling leads to the ordered low-spin phase (b), illumination with green light yields the ordered high-spin phase (c), annealing at 110 K followed by slow cooling results in the disordered low-spin phase (d), and repeated illumination gives the disordered high-spin phase (e).