Inverse spin crossover in fluorinated Fe(1,10-phenanthroline)<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg" display="inline" id="d1e328"><mml:msub><mml:mrow /><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math>(NCS)<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si4.svg" display="inline" id="d1e336"><mml:msub><mml:mrow /><mml:mrow><mml:mn>2</mml:mn></mml:mrow></mml:msub></mml:math> adsorbed on Cu (001) surface

Density functional theory (DFT) including van der Waals weak interaction in conjunction with the so called rotational invariant DFT+U, where U is Hubbard of iron site, used to show that fluorinated spin crossover Fe(phen)2(NCS)2 molecule whether gas phase or adsorbed on Cu(001) surface switches from original low state high state. The calculated minimal energy path by means both nudged elastic band method and constrained minimization found be smaller for molecule. Using Bader electron density analysis a point charge model, this inversion explained terms doping Fe-octahedron cage which led an increase Fe–N bond lengths distortion Fe(II) octahedron. Consequently, ligand-field splitting drastically reduced, making high-spin ground more stable than low-spin scanning tunneling microscopy (STM) images Tersoff–Hamann approximation clear distinction between unfluorinated This theoretical prediction awaiting future STM experimental confirmation.