# Survey of classical density functionals for modelling hydrogen physisorption at 77K.
> 77Kにおける水素物理吸着モデリングのための古典密度汎関数法の比較検討


## Abstract

This study evaluates classical density functional methods for describing quantum dispersion effects in physisorbed hydrogen at 77K. Two approaches were compared: the open ring approximation (ORA) developed by Broukhno et al. and the Feynman-Hibbs (FH) semiclassical approximation. Both methods employed a standard classical density functional to represent hydrogen molecule-molecule interactions. Benchmarking was performed using the three-dimensional quantum harmonic oscillator system and a graphitic slit pore adsorption model. Results were assessed against path-integral Monte Carlo simulations and exact analytical solutions. Neither approach proved fully adequate; however, at 77K the ORA-based method generally outperformed the FH-based method owing to a fortuitous cancellation of errors within the density functionals employed. The FH approach would become superior if more accurate excess functionals were incorporated.

## Bibliographic

- **Authors**: Sweatman MB
- **Journal**: Phys Rev E Stat Nonlin Soft Matter Phys
- **Year**: 2008
- **PMID**: [18352153](https://pubmed.ncbi.nlm.nih.gov/18352153/)
- **DOI**: [10.1103/PhysRevE.77.026712](https://doi.org/10.1103/PhysRevE.77.026712)
- **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 18352153. https://h2-papers.org/en/papers/18352153
> **Source**: PubMed PMID [18352153](https://pubmed.ncbi.nlm.nih.gov/18352153/)