Perturbation theory for water with an associating reference fluid.

Area of Science:

• Physical Chemistry
• Thermodynamics
• Computational Chemistry

Background:

• Standard perturbation theories struggle with water's tetrahedral structure.
• Spherically symmetric assumptions fail to capture liquid water properties accurately.

Purpose of the Study:

• To develop a more accurate theoretical model for water thermodynamics.
• To address limitations of existing perturbation theories for water.

Main Methods:

• Introduced Associated Reference Perturbation Theory (APT).
• Treated reference fluid as an associating hard sphere fluid.
• Calculated transition to tetrahedral symmetry self-consistently.
• Applied second-order Barker-Henderson perturbation for attractions.

Main Results:

• APT accurately describes water's structural transition.
• The model provides a significantly improved description of water properties.
• Achieved theoretical self-consistency without molecular simulations.

Conclusions:

• Associated Reference Perturbation Theory (APT) offers a superior framework for water thermodynamics.
• This approach overcomes key limitations of traditional perturbation theories.
• APT enables accurate theoretical predictions of liquid water behavior.