Identifying Tm@C82 isomers with density functional theory calculations.

Area of Science:

• Computational chemistry
• Materials science
• Nanotechnology

Background:

• Endohedral metallofullerenes (EMFs) are fullerenes encapsulating atoms or ions.
• Understanding the structure and properties of EMF isomers is crucial for their applications.
• Thulium-based EMFs, Tm@C(82), present unique electronic and stability characteristics.

Purpose of the Study:

• To investigate the geometrical and electronic properties of Tm@C(82) isomers using computational methods.
• To identify energetically favorable isomers and correlate them with experimental observations.
• To elucidate the interaction between the encapsulated Tm atom and the C(82) cage.

Main Methods:

• Density functional theory (DFT) calculations were employed.
• Geometrical optimizations and electronic structure analyses were performed.
• Simulations of ultraviolet photoelectron spectra (UPS) were conducted for comparison with experimental data.

Main Results:

• Three energetically favorable Tm@C(82) isomers with C(s), C(2), and C(2v) symmetries were identified.
• Calculated isomers are consistent with experimental nuclear magnetic resonance (NMR) findings.
• Simulated UPS spectra closely match experimental measurements, validating the proposed structures.
• A new assignment for the experimentally observed Tm@C(82) isomer with C(s) symmetry was proposed, showing improved agreement with data.
• Strong interaction between the endohedral Tm atom and the C(82) cage was observed.

Conclusions:

• The study successfully identified and characterized stable Tm@C(82) isomers, providing insights into their structural and electronic properties.
• The findings offer a better understanding of the factors influencing the stability of metallofullerene isomers.
• The results contribute to the accurate assignment of experimental data for Tm@C(82) and similar EMFs.