A four-dimensional potential energy surface for the Ar-D2O van der Waals complex: Bending normal coordinate...

Area of Science:

• Physical Chemistry
• Molecular Physics
• Spectroscopy

Background:

• Understanding intermolecular interactions is crucial for molecular spectroscopy.
• The Ar-D2O complex serves as a model system for studying van der Waals forces and hydrogen bonding.

Purpose of the Study:

• To construct a high-accuracy four-dimensional potential energy surface (PES) for the Ar-D2O complex.
• To calculate bound state energies and predict infrared (IR) spectra for Ar-D2O.
• To validate the theoretical model against experimental spectroscopic data.

Main Methods:

• Ab initio calculations using the coupled-cluster singles and doubles with noniterative inclusion of triples [CCSD(T)] method.
• A large basis set augmented with bond functions was employed.
• Vibrationally averaged PESs were generated by integrating over the D2O bending normal coordinate (Q2).

Main Results:

• A four-dimensional PES for the Ar-D2O system was reported.
• Theoretical infrared transition frequencies for 104 lines were calculated.
• The predicted frequencies show good agreement with existing experimental values for various transitions.

Conclusions:

• The developed PES accurately describes the Ar-D2O interaction.
• The theoretical predictions support experimental observations of Ar-D2O infrared spectra.
• This work provides a valuable theoretical benchmark for future spectroscopic studies of similar complexes.