# Partition Functions and Thermodynamic Quantities for the Molecular Hydrogen Isotopologues.
> 水素同位体分子の分配関数と熱力学的諸量の精密計算


## Abstract

This study computed partition functions and thermodynamic quantities for molecular hydrogen isotopologues by employing rovibrational energy levels derived from highly accurate adiabatic potential energy surfaces established by Pachucki and Komasa. All bound energy levels up to the dissociation limit were incorporated, along with quasi-bound levels situated below the centrifugal potential barriers. For homonuclear species—H2, D2, and T2—the partition functions and thermodynamic properties of normal mixtures were evaluated using a statistical framework proposed by Colonna et al., which defines the mixture partition function in a manner that eliminates inconsistencies in thermodynamic quantities directly dependent on the internal partition function, particularly in the high-temperature regime.

### Mechanism

Rovibrational energy levels, including quasi-bound states below centrifugal barriers, were derived from adiabatic potential energy functions and used to construct partition functions; thermodynamic inconsistencies at high temperatures were resolved by applying a mixture-based partition function definition.

## Bibliographic

- **Authors**: Zúñiga J, Bastida A, Requena A, Cerezo J
- **Journal**: J Phys Chem A
- **Year**: 2021 (2021-10-21)
- **PMID**: [34613734](https://pubmed.ncbi.nlm.nih.gov/34613734/)
- **DOI**: [10.1021/acs.jpca.1c06468](https://doi.org/10.1021/acs.jpca.1c06468)
- **PMC**: [PMC8543445](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8543445/)
- **Study type**: other
- **Delivery route**: not specified
- **Effect reported**: not assessed

## Delivery context

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

## Safety notes

The delivery route is not clearly identifiable from this paper. For hydrogen intake, inhalation is the most efficient route; inhalation, however, carries explosion risk (empirical LFL of 10%; high-concentration devices are not recommended).

See also:
- [Inhalation concentration and LFL / UFL](https://h2-papers.org/en/safety-notes/inhalation-concentration)
- [Consumer Affairs Agency accident cases](https://h2-papers.org/en/safety-notes/accident-cases)

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> **Cite as**: H2 Papers — PMID 34613734. https://h2-papers.org/en/papers/34613734
> **Source**: PubMed PMID [34613734](https://pubmed.ncbi.nlm.nih.gov/34613734/)