Geometric and electronic structures of FeB_n^-/0/+ clusters (n = 1-3): insights from advanced computational methods

Area of Science:

• Computational Chemistry
• Materials Science
• Quantum Mechanics

Background:

• Boron-doped iron clusters (FeB_n^-/0/+) are crucial for materials science.
• Previous studies lack comprehensive understanding of small FeB_n^-/0/+ cluster structures.
• This research addresses the need for detailed insights into their geometric and electronic properties.

Purpose of the Study:

• To investigate the ground and low-lying excited states of FeB_n^-/0/+ clusters (n=1-3).
• To determine detachment and ionization energies of these clusters.
• To elucidate the structural and electronic characteristics of FeB_n^-/0/+ systems.

Main Methods:

• Employed Density Functional Theory (DFT) for geometry optimization and vibrational frequency calculations.
• Utilized multireference methods including CASPT2, RASPT2, and DMRG-CASPT2 for electronic structure analysis.
• Performed Franck-Condon factor simulations for vibrational transitions.

Main Results:

• Identified ground states for FeB^-/0/+ as ³Σ^-, ⁴Σ^-, and ³Σ^- respectively.
• Determined cyclic isomers as most stable for FeB₂^-/0/+ and tetrahedral/rhombic structures for FeB₃^-/0/+.
• Observed increasing detachment energies from FeB^- to FeB₃^- and rising ionization energies for neutral clusters.

Conclusions:

• The study provides a detailed understanding of the electronic and geometric structures of FeB_n^-/0/+ clusters.
• Structural preferences and electronic properties correlate with the number of boron atoms and cluster charge.
• Findings offer valuable data for designing novel materials based on boron-doped iron clusters.