Interplay between charge and vibrational delocalization in cationic helium clusters

Area of Science:

• Quantum Chemistry
• Atomic and Molecular Physics
• Low-Temperature Physics

Background:

• Understanding the behavior of charged atomic clusters is crucial for various fields.
• Helium clusters, particularly cationic ones, present unique quantum mechanical properties due to their light mass and weak interactions.

Purpose of the Study:

• To theoretically investigate the stable structures and low-temperature thermodynamics of cationic helium clusters.
• To elucidate the charge distribution and structural dynamics within these clusters.

Main Methods:

• Utilized a diatomics-in-molecules (DIM) model for potential energy surfaces.
• Employed a quantum mechanical computational framework treating both electronic and nuclear degrees of freedom.
• Analyzed stable structures and thermodynamic properties at low temperatures.

Main Results:

• Identified that the charge is typically localized on two helium atoms in smaller clusters.
• Demonstrated significant vibrational delocalization of charge across multiple atoms in clusters with five or more helium atoms.
• Observed that large cationic helium clusters behave as fluids with a defined solvation shell around the charged core.

Conclusions:

• Cationic helium clusters exhibit complex charge distribution influenced by vibrational delocalization.
• The fluid-like nature and solvation shell formation in large clusters are key findings.
• Theoretical insights provide a foundation for understanding quantum effects in atomic clusters.