Quantum Simulation Verifies the Stability of an 18-Coordinated Actinium-Helium Complex
Eiki Ozama1, Sadia Adachi1, Toshiyuki Takayanagi1
1Department of Chemistry, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama City, Saitama, 338-8570, Japan.
Chemistry (Weinheim an Der Bergstrasse, Germany)
|June 20, 2018
Summary
Quantum simulations reveal actinium ions (Ac3+) in helium clusters (Ac3+ ⋅Hen) exhibit stable structures. Nuclear quantum effects influence vibrational amplitude, with up to eighteen helium atoms forming a D4d symmetric solvation shell.
Area of Science:
- Atomic and Molecular Physics
- Quantum Chemistry
- Condensed Matter Physics
Background:
- Actinium ions (Ac3+) are studied within helium clusters (Ac3+ ⋅Hen) to understand solvation phenomena.
- Low-temperature environments (1-3 K) are crucial for the stability of these complexes.
- Investigating the role of nuclear quantum effects in atomic cluster behavior is essential.
Purpose of the Study:
- To elucidate the structural properties of trivalent actinium cations within helium clusters.
- To determine the influence of cluster size on the stability and rigidity of Ac3+ ⋅Hen complexes.
- To explore the coordination number and symmetry of helium atoms surrounding the actinium ion.
Main Methods:
- Quantum path integral molecular dynamics (QPID) simulations were employed.
- Simulations covered a range of cluster sizes (n=18-200).
- Relativistic ab initio calculations provided an accurate Ac3+ -He interaction potential.
Main Results:
- The nuclear quantum effect of helium atoms significantly impacts the vibrational amplitude of the Ac3+ -He complex.
- A maximum coordination number of eighteen helium atoms was observed for the first solvation shell.
- The helium atoms in the first solvation shell adopt a D4d symmetry around the actinium ion.
Conclusions:
- The Ac3+ -He18 complex demonstrates increased rigidity and stability with larger cluster sizes.
- Quantum effects are vital for understanding the dynamics of actinium ions in helium environments.
- The findings provide insights into the structure and stability of heavy element ions in quantum fluids.
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