Molecular modeling was performed using quantum-chemical hybrid density functional theory (DFT) computations. The eclipsed conformation of FeCp₂ (see table ) was assumed, as it has been demonstrated to be slightly more energetically favourable in vacuum compared to the staggered conformation, both by computations and experiments . The quantumchemical computations (energy computations, geometry optimizations, frequency calculations and thermodynamics) were performed using the Gaussian 16 software package with the B3LYP exchange-correlation functional , together with D3-Grimme dispersion correction. The def2tzvp basis set was used for the iron atom, and 6-311G(2df,2pd) basis set was used for all other atoms. This mixed basis set has been shown to produce valid thermochemical results compared to experimental ferrocene formation enthalpies. For the anionic and radical species, diffuse functions were used. The diffuse functions were only added on C and H, as the electronic charge is not expected to distribute on Fe due to its low reduction potential. The frequencies and thermochemical properties were calculated at a temperature of T = 298.15 K and pressure of p = 1 atm. To calculate the enthalpies (ΔrH) and Gibbs free energies (ΔrG) of reactions involving electron participation, the enthalpy of the electron was taken as 3.1351 kJ/mol, and the Gibbs free energy as -3.6160 kJ/mol. The electronic energy (ΔrE) of the electron was assumed to be 0 kJ/mol, reflecting the convention that an electron at absolute zero has no energy. The recorded emission spectra from the Ar and FeCp2 plasma can be seen in Fig. and Fig.