Methane-water cross second virial coefficient with quantum corrections from an ab initio potential

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Thermodynamics

Background:

• Accurate thermodynamic property prediction is crucial for chemical processes.
• The methane-water system is relevant in various industrial applications.
• Ab initio potentials are essential for high-fidelity molecular simulations.

Purpose of the Study:

• To calculate the cross second virial coefficient (B12) and related quantity phi12 for the methane-water system.
• To incorporate quantum corrections into classical calculations.
• To provide an analytical expression for B12(T) and assess experimental data quality.

Main Methods:

• Ab initio potentials were used for methane-water interactions.
• Quantum corrections of order hbar^2 were applied to classical calculations.
• Calculated values were fitted to derive an analytical expression for B12(T).

Main Results:

• Calculations of B12 and phi12 were performed for temperatures ranging from 200 to 1000 K.
• Uncertainties in computed values were estimated, aiding experimental data evaluation.
• An accurate analytical expression for B12(T) was derived, also predicting phi12(T).

Conclusions:

• The study provides reliable B12 and phi12 values for the methane-water system.
• The derived analytical expression offers a practical tool for predicting these properties.
• The work validates the accuracy of the ab initio potential used and quantum correction methods.