Comprehensive Modeling of Acetone Clusters: QTAIM Analysis and QCE Study

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Molecular Dynamics

Background:

• Understanding macroscopic solvent properties from microscopic interactions is challenging.
• Polar aprotic solvents like acetone require detailed molecular-level analysis.

Purpose of the Study:

• To bridge the gap between cluster-scale interactions and macroscopic liquid acetone properties.
• To develop a validated computational framework for predicting liquid-phase properties from ab initio cluster data.

Main Methods:

• Utilized the ABCluster algorithm for potential energy surface exploration.
• Performed high-level density functional theory (DFT) calculations (MN12SX-D3/def2-TZVP).
• Applied Quantum Theory of Atoms in Molecules (QTAIM) and Quantum Cluster Equilibrium (QCE) theory.

Main Results:

• Identified a cooperative network of dipole-dipole O⋯C and O⋯O interactions, with supporting weak contacts.
• QCE theory predicted a temperature-dependent cluster distribution, favoring monomers at higher temperatures.
• The model accurately reproduced experimental thermodynamic properties (heat capacity) and infrared spectra.

Conclusions:

• Macroscopic properties of liquid acetone arise from a dynamic equilibrium of small, weakly-bound clusters.
• The integrated DFT-QTAIM-QCE approach provides a validated computational framework for liquid properties.
• This work offers the first complete QCE characterization of pure liquid acetone.