The HS → LS relaxation under external pressure in the Fe(II) spin-crossover system [Zn 1− xFe x(ptz) 6](BF 4) 2(ptz = 1-propyltetrazole, x = 0.1)

Abstract

At low temperatures an external pressure of 1 kbar accelerates the high-spin → low-spin relaxation in the [Zn 1− x Fe x (ptz) 6](BF 4) 2, x = 0.1, spin-crossover system by one order of magnitude. This is due to the large difference in volume between the high-spin and low-spin states of 26 Å 3/molecule. The relative vertical and horizontal shifts of the potential wells of the two states as a function of pressure are estimated to be 130 cm −1/kbar and 10 −3 Å/kbar, respectively.