# Embracing local suppression and enhancement of dynamic correlation effects in a CASΠDFT method for efficient description of excited states.
> 励起状態の効率的な記述のための動的相関効果の局所的抑制と増強を取り入れたCASΠDFT法


## Abstract

This paper concerns a quantum chemical methodology (CASπDFT) that is entirely unrelated to molecular hydrogen biomedical research. The method integrates a complete active space wavefunction for nondynamic correlation with a DFT correlation functional modified by a local on-top pair density correction function. Spatial regions of correlation suppression and enhancement arise from covalent and ionic wavefunction configurations, respectively. Validation on hydrogen molecule potential energy curves for excited states and on n→π* and π→π* excitations of six-membered nitrogen heterocycles (pyridine, pyrazine, pyrimidine, pyridazine) showed an absolute average error 0.1 eV below CCSD and 0.1 eV above CC3, achieved at negligible computational cost relative to coupled cluster approaches.

## Bibliographic

- **Authors**: Pernal K, Gritsenko O
- **Journal**: Faraday Discuss
- **Year**: 2020 (2020-12-04)
- **PMID**: [32945307](https://pubmed.ncbi.nlm.nih.gov/32945307/)
- **DOI**: [10.1039/d0fd00050g](https://doi.org/10.1039/d0fd00050g)
- **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 32945307. https://h2-papers.org/en/papers/32945307
> **Source**: PubMed PMID [32945307](https://pubmed.ncbi.nlm.nih.gov/32945307/)