Structures of DMSO clusters and quantum cluster equilibrium (QCE).

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Chemical Physics

Background:

• Dimethylsulfoxide (DMSO) clusters are vital for comprehending liquid DMSO behavior.
• Their potential energy surfaces (PESs) are complex and have been largely unexplored.
• Understanding these clusters is crucial for accurate modeling of DMSO's properties.

Purpose of the Study:

• To explore the potential energy surfaces (PESs) of dimethylsulfoxide (DMSO) clusters from dimer to decamer.
• To investigate the binding energies, enthalpies, and topological properties of stable DMSO isomers.
• To apply quantum cluster equilibrium (QCE) theory to predict the properties of liquid DMSO.

Main Methods:

• Classical molecular dynamics simulations to explore PESs.
• Full geometry optimizations using the PW6B95-D3/def2-TZVP level of theory.
• Quantum Theory of Atoms in Molecules (QTAIM) analysis for isomer characterization.
• Quantum Cluster Equilibrium (QCE) theory application to liquid DMSO.

Main Results:

• Detailed mapping of DMSO cluster PESs from dimer to decamer.
• Identification of dominant cluster configurations (dimer and decamer) in liquid DMSO.
• Prediction of liquid DMSO properties, including population distribution and infrared spectrum.
• The predicted infrared spectrum of liquid DMSO shows qualitative agreement with experimental data.

Conclusions:

• The study successfully characterized DMSO clusters and their PESs.
• QCE theory effectively predicts liquid DMSO properties based on cluster populations.
• DMSO dimers and decamers are the primary contributors to the liquid state.
• This work provides a foundation for further computational studies of DMSO and similar liquids.