Data Sheet 1_Computational investigation of spin-resolved energy landscapes of FeC4H2+ and their astrochemical implications.docx

The enduring enigma of iron depletion in the interstellar medium serves as a compelling impetus for an in-depth exploration of iron-bearing molecular species. The cationic system FeC4H2+ is theoretically explored in the doublet, quartet, and sextet electronic states using density functional theory. The geometry corresponding to the least energy within the quartet state represents the global minimum, thus substantiating the assertion that the quartet constitutes the ground state of this particular system. The bonding characterization of the three lowest-energy geometries across the three electronic states is explored using quantum-chemical tools, including Wiberg bond indices, natural atomic charges, and the electron localization function. The recent detection of the FeC radical in the interstellar medium implies that the investigated systems are strong candidates for radioastronomical observation and contribute to the body of knowledge on iron chemistry in the cosmos.