The Challenge of ab Initio Calculations in Small Neon Clusters

Area of Science:

• Computational Chemistry
• Quantum Chemistry
• Atomic and Molecular Physics

Background:

• Weakly bound clusters are fundamental in understanding intermolecular forces.
• Accurate theoretical descriptions of noble gas clusters are challenging due to weak interactions.

Purpose of the Study:

• To investigate the ground-state binding energies and structural properties of neon dimer, trimer, and tetramers.
• To develop and validate new SIGMA-s basis sets for studying weakly bound systems.
• To assess the accuracy of different basis sets and computational levels for these systems.

Main Methods:

• High-level ab initio calculations using Hartree-Fock (HF) and Coupled Cluster with Singles and Doubles and perturbative Triples (CCSD(T)) methods.
• Utilized Dunning, Augmented Near-Optimized (ANO), and newly developed SIGMA-s basis sets of varying sizes.
• Computed total energies, atomization energies, correlation energies, and equilibrium distances.

Main Results:

• Determined ground-state binding energies and structural parameters for neon clusters (Ne2, Ne3, Ne4).
• Demonstrated the effectiveness of the SIGMA-s basis sets for accurately describing weak interactions.
• Evaluated the impact of basis set size and augmentation on calculated properties.

Conclusions:

• The developed SIGMA-s basis sets provide accurate results for weakly bound neon systems.
• Extrapolation methods can reliably predict stabilization energies for larger systems.
• This work offers a benchmark for future studies on noble gas clusters.