First principle study of AlX (X=3d, 4d, 5d elements and Lu) dimer

Area of Science:

• Materials Science
• Computational Chemistry
• Quantum Chemistry

Background:

• Aluminum (Al) is a versatile element with diverse applications.
• Understanding the bonding characteristics of aluminum with transition metals is crucial for designing novel alloys and materials.
• Previous studies have explored various Al-metal interactions, but a systematic investigation across d-block elements and related groups is needed.

Purpose of the Study:

• To computationally investigate the ground state equilibrium bond lengths, harmonic vibrational frequencies, and dissociation energies of AlX dimers, where X represents 3d, 4d, 5d transition metals and lutetium (Lu).
• To compare the bonding strengths of early vs. late transition metals with aluminum.
• To evaluate the suitability of lutetium as a replacement for lanthanum in periodic trends and assess the aluminum-zinc group metal interactions.

Main Methods:

• Density Functional Theory (DFT) using the B3LYP functional was employed for all calculations.
• The study focused on determining key molecular properties: equilibrium bond length, harmonic vibrational frequency, and dissociation energy.
• Results were compared with existing experimental and theoretical data for validation.

Main Results:

• Calculated properties for most AlX dimers align well with experimental and theoretical data, with a noted discrepancy for AlCr dissociation energy.
• Late transition metals (e.g., 4d, 5d) exhibit stronger bonding with aluminum compared to early transition metals.
• Lutetium (Lu) demonstrates bonding characteristics that make it a more appropriate periodic analog for Lanthanum (La) than previously considered.
• Aluminum dimers with zinc (Zn), cadmium (Cd), and mercury (Hg) show very weak bonding interactions.

Conclusions:

• The findings provide valuable insights into the electronic structure and bonding of AlX dimers, particularly highlighting the trend of stronger Al-late transition metal interactions.
• The study supports the re-evaluation of lutetium's position relative to lanthanum in the periodic table based on bonding behavior.
• The weak interactions between aluminum and group 12 elements (Zn, Cd, Hg) suggest limited applicability in forming stable alloys with aluminum.