Theoretical design of stable small aluminium-magnesium binary clusters

Area of Science:

• * Computational chemistry and materials science.
• * Investigating the electronic and structural properties of bimetallic clusters.

Background:

• * Bimetallic clusters are crucial in catalysis and materials science, but predicting their stability is challenging.
• * Existing models like the Hückel model and phenomenological shell model (PSM) require validation for new systems.

Purpose of the Study:

• * To evaluate the effectiveness of simple electron counting rules and the PSM for designing stable Al-Mg clusters.
• * To identify stable Al(x)Mg(y) (x, y = 1-4) bimetallic cluster structures.
• * To analyze the thermodynamic stability and electronic structure of these clusters.

Main Methods:

• * Exploration of potential energy surfaces for Al(x)Mg(y) clusters.
• * Application of the 4n + 2 Hückel model and the phenomenological shell model (PSM).
• * Calculation of fragmentation energies and electronic structure analysis.

Main Results:

• * Feasible design of stable Al-Mg clusters using electron counting rules and PSM.
• * Identification of three stable clusters: Al(4)Mg, Al(2)Mg(2), and Al(4)Mg(4).
• * Al(4)Mg stability attributed to a stable Al(4)(2-) subunit with a Mg(2+) adatom; Al(2)Mg(2) and Al(4)Mg(4) exhibit 3D structures with closed-shell electron counts (10 and 20, respectively) in the PSM.

Conclusions:

• * Simple electron counting rules and the PSM are effective tools for predicting stable bimetallic Al-Mg clusters.
• * The study validates and extends the applicability of these models to small Al-Mg systems.
• * Identified stable clusters provide a basis for further research in cluster science and applications.