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Path-integral calculation of the second virial coefficient including intramolecular flexibility effects
Giovanni Garberoglio1, Piotr Jankowski2, Krzysztof Szalewicz3
1Interdisciplinary Laboratory for Computational Science (LISC), FBK-CMM and University of Trento, via Sommarive 18, I-38123 Povo (TN), Italy.
The Journal of Chemical Physics
|August 3, 2014
Summary
We developed a quantum calculation method for the second virial coefficient, including molecular flexibility. This approach accurately models hydrogen and deuterium behavior, validating its effectiveness across a wide temperature range.
Area of Science:
- Quantum chemistry
- Statistical mechanics
- Molecular physics
Background:
- The second virial coefficient is crucial for understanding gas behavior.
- Previous calculations often neglected intramolecular flexibility.
- Accurate modeling of molecular interactions is essential for physical chemistry.
Purpose of the Study:
- To present a novel path-integral Monte Carlo procedure for calculating the second molecular virial coefficient.
- To incorporate intramolecular flexibility into quantum mechanical calculations.
- To apply this method to molecular hydrogen (H2) and deuterium (D2).
Main Methods:
- Path-integral Monte Carlo simulation.
- Fully quantum mechanical approach.
- Accounting for intramolecular flexibility in H2 and D2.
Main Results:
- The effect of molecular flexibility on the second virial coefficient is significant.
- Results for H2 and D2 show good agreement with experimental data.
- Discrepancies were noted for H2 between 100 and 200 K compared to some equations of state.
Conclusions:
- The developed method provides accurate quantum calculations of the second virial coefficient.
- Intramolecular flexibility is a key factor in the behavior of H2 and D2.
- The study highlights the limitations of some empirical equations of state in specific temperature ranges.
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