All-atom molecular dynamics simulation of the [Fe(pyrazine)][Ni(CN)4] spin-crossover complex. II. Spatiotemporal study of a bimorph actuator

Abstract

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Quantification of the thermodynamic effects of the low-spin – high-spin interaction in molecular crystals of a mononuclear iron(ii) spin crossover complex.

“…1 a The cooperative spin transition is determined by two main factors: (i) the molecular structure, determining the structural and vibrational properties of the supramolecular lattice and (ii) elastic and surface effects which can be theoretically predicted using Spiering's model 5 based on elasticity theory as well as Molecular Dynamics (MD) simulations. 6,7 To gain a comprehensive understanding of the requirements for an abrupt spin transition in molecular SCO compounds, it is desirable to model the structural and vibrational lattice properties and especially to rationalize how the spin states of the neighbouring molecules influence the structure and hence the energy and entropy of the spin transition in a given spin centre. In other words, it is important to model the short-range interactions between the neighbouring molecules of different spin state.…”

“…It should be noted that intermolecular interactions also have been modelled for Fe(phen) 2 (NCS) 2 and Fe(picolylamine) 3 2+ (ref. 7–10) with solid state DFT calculations using the PBE functional. 16 The approach presented here is based on molecular DFT calculations which allow the use of higher level functionals as well as the estimation of vibrational and thus entropic effects.…”