Hydrogen bonding inside and outside carbon nanotubes: HF dimer as a case study

Area of Science:

• Computational chemistry
• Materials science
• Nanotechnology

Background:

• Noncovalent interactions are crucial for molecular complex behavior.
• Single-walled carbon nanotubes (SWCNTs) possess unique properties due to their structure.
• Hydrogen fluoride (HF) dimer is a fundamental hydrogen-bonded system.

Purpose of the Study:

• To investigate the noncovalent interactions between HF dimer and SWCNTs of varying diameters.
• To analyze the influence of confinement and orientation on interaction energies.
• To study charge distribution changes in HF-SWCNT complexes.

Main Methods:

• Theoretical calculations using the M06-2X exchange-correlation functional.
• Supermolecular approach for modeling HF dimer-SWCNT complexes.
• Energy scans and Natural Bond Orbital (NBO) analysis.

Main Results:

• Interaction energy is significantly influenced by the HF dimer's position (endohedral vs. exohedral) and SWCNT diameter.
• HF dimer exhibits stronger binding affinity towards the interior of SWCNTs.
• Charge distribution analysis reveals specific interactions within the complexes.
• Basis set superposition error (BSSE) is notably enhanced.

Conclusions:

• The spatial arrangement and SWCNT diameter critically affect HF dimer binding.
• SWCNT interiors offer a more favorable environment for HF dimer adsorption.
• Understanding these interactions is key for designing novel nanomaterials and predicting molecular behavior within confined spaces.