Calculations (all) Calculations (filtered) The observed changes in experimental and computed quadrupole splitting values can be traced back to the interlinked electronic and molecular structures. For an iron(II) high spin complex, one d orbital is doubly occupied. In the equilibrium structure, this is d xz , see Figure . When the structure is distorted along the normal coordinates, different orbitals can be stabilized, leading to different electronic configurations, hence different electric field gradients and thus ultimately different quadrupole splitting values. For [Fe(TPP)(2-MeHIm)], two relevant electronic configurations were identified. In one configuration, three electrons are distributed between the d xz and d yz orbitals, with the exact distribution depending on the deformation of the molecule and the mixing of those two orbitals. In the other configuration, the electrons are distributed between the d x 2 -y 2 and d xy orbitals. This is represented in We note that filtering out just the (d xz , d yz ) 3 configuration better reproduces the trend in the temperature dependence of the quadrupole splitting (see Table and Figure ), albeit with a more pronounced discrepancy with the experimental values. The three data points lie on a line parallel to the ideal line with a slope of 1. We interpret from this observation that Wigner sampling adequately captures the component of the vibrationally induced temperature dependence of the quadrupole splitting in Mössbauer spectroscopy. This means that the remaining discrepancy with the experimental data must stem from data points with a different electronic configuration, potentially including spin-crossover effects. This is likely not adequately captured by the single-determinant DFT calculations used here.