Computing vibration-rotation-tunnelling levels of HOD dimer.

Area of Science:

• Chemical Physics
• Quantum Mechanics
• Spectroscopy

Background:

• Water dimer interactions are fundamental to understanding hydrogen bonding.
• Previous studies on HOD dimer have used simplified models.
• Accurate potential energy surfaces are crucial for theoretical calculations.

Purpose of the Study:

• To compute vibration-rotation-tunnelling (VRT) levels of the HOD dimer.
• To validate the accuracy of a 6D water dimer potential energy surface.
• To compare computed results with experimental data for HOD dimer isomers.

Main Methods:

• Utilized an accurate 6D potential energy surface for the HOD dimer.
• Assumed rigid monomers during computation.
• Calculated VRT energy levels and tunnelling splittings.

Main Results:

• Computed VRT levels for both D-bonded and H-bonded isomers of HOD dimer.
• Observed wavefunctions with amplitude in four wells for both isomers.
• Achieved good agreement between computed and experimental tunnelling splittings.

Conclusions:

• The 6D potential energy surface accurately predicts HOD dimer VRT levels.
• Computed results support the testing and refinement of water dimer potentials.
• The study demonstrates the importance of HOD dimer for validating theoretical models.