Sub 20 cm-1 computational prediction of the CH bond energy - a case of systematic error in computational thermochemistry.
Phys Chem Chem Phys
; 25(32): 21162-21172, 2023 Aug 16.
Article
em En
| MEDLINE
| ID: mdl-36200428
ABSTRACT
The bond dissociation energy of methylidyne, D0(CH), is studied using an improved version of the High-Accuracy Extrapolated ab initio Thermochemistry (HEAT) approach as well as the Feller-Peterson-Dixon (FPD) model chemistry. These calculations, which include basis sets up to nonuple (aug-cc-pCV9Z) quality, are expected to be capable of providing results substantially more accurate than the ca. 1 kJ mol-1 level that is characteristic of standard high-accuracy protocols for computational thermochemistry. The calculated 0 K CH bond energy (27 954 ± 15 cm-1 for HEAT and 27 956 ± 15 cm-1 for FPD), along with equivalent treatments of the CH ionization energy and the CH+ dissociation energy (85 829 ± 15 cm-1 and 32 946 ± 15 cm-1, respectively), were compared to the existing benchmarks from Active Thermochemical Tables (ATcT), uncovering an unexpected difference for D0(CH). This has prompted a detailed reexamination of the provenance of the corresponding ATcT benchmark, allowing the discovery and subsequent correction of a systematic error present in several published high-level calculations, ultimately yielding an amended ATcT benchmark for D0(CH). Finally, the current theoretical results were added to the ATcT Thermochemical Network, producing refined ATcT estimates of 27 957.3 ± 6.0 cm-1 for D0(CH), 32 946.7 ± 0.6 cm-1 for D0(CH+), and 85 831.0 ± 6.0 cm-1 for IE(CH).
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Coleções:
01-internacional
Base de dados:
MEDLINE
Tipo de estudo:
Guideline
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Prognostic_studies
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Risk_factors_studies
Idioma:
En
Revista:
Phys Chem Chem Phys
Assunto da revista:
BIOFISICA
/
QUIMICA
Ano de publicação:
2023
Tipo de documento:
Article
País de afiliação:
Estados Unidos