Nondynamical correlation effects in multidimensional potential energy curves of prototypical hydrocarbons

Author(s)
Karton, Amir
Publication Date
2025-01-15
Abstract
<p>We demonstrate that simultaneously stretching all bonds in a molecule by small increments provides a systematic approach to gradually increasing its multireference character. We show this for four hydrocarbons — methane, ethane, ethylene, and acetylene — each representing a progressively more complex electronic structure. The <i>T</i><sub>1</sub>, <i>D</i><sub>1</sub>, and %TAE[(T)] multireference diagnostics increase as all the bonds are stretched simultaneously. The post-CCSD(T) correlation components of the total atomization energy (TAE) up to CCSDTQ systematically increase as the bonds are stretched. The extent of the increase in the multireference character correlates with the complexity of the electronic structure in the order methane → ethane → ethylene → acetylene. The CCSDTQ/CBS multidimensional potential energy curves serve as benchmarks for assessing the performance of DFT methods for strong correlation effects. The conventional DFT methods B97-D, TPSS, and TPSSh and double-hybrid DFT methods are more robust toward multireference effects.</p>
Citation
Chemical Physics, v.589, p. 1-10
ISSN
1873-4421
0301-0104
Link
Publisher
Elsevier BV
Title
Nondynamical correlation effects in multidimensional potential energy curves of prototypical hydrocarbons
Type of document
Journal Article
Entity Type
Publication

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