Title :

Critical evaluation of the potential energy surface of the CH3 + HO2 reaction system

Author(s) :

Faragó, Eszter Pongráczné [Auteur]
University of Szeged [Szeged]
Szőri, M. [Auteur]
University of Szeged [Szeged]
Owen, M.C. [Auteur]
Forschungszentrum Jülich GmbH | Centre de recherche de Jülich | Jülich Research Centre [FZJ]
University of Szeged [Szeged]
Fittschen, Christa [Auteur]
Physicochimie des Processus de Combustion et de l’Atmosphère - UMR 8522 [PC2A]
Viskolcz, B. [Auteur]
University of Szeged [Szeged]

Journal title :

Journal of Chemical Physics

Volume number :

142

Publication date :

2015

HAL domain(s) :

Chimie/Chimie théorique et/ou physique
Physique [physics]/Physique [physics]/Chimie-Physique [physics.chem-ph]

English abstract : [en]

The CH3 + HO2 reaction system was studied theoretically by a newly developed, HEAT345-(Q) method based CHEAT1 protocol and includes the combined singlet and triplet potential energy surfaces. The main simplification is ...
Show more >The CH3 + HO2 reaction system was studied theoretically by a newly developed, HEAT345-(Q) method based CHEAT1 protocol and includes the combined singlet and triplet potential energy surfaces. The main simplification is based on the CCSDT(Q)/cc-pVDZ calculation which is computationally inexpensive. Despite the economic and black-box treatment of higher excitations, the results are within 0.6 kcal/mol of the highly accurate literature values. Furthermore, the CHEAT1 surpassed the popular standard composite methods such as CBS-4M, CBS-QB3, CBS-APNO, G2, G3, G3MP2B3, G4, W1U, and W1BD mainly due to their poor performance in characterizing transition states (TS). For TS structures, various standard DFT and MP2 method have also been tested against the resulting CCSD/cc-pVTZ geometry of our protocol. A fairly good agreement was only found in the cases of the B2PLYP and BHandHLYP functionals, which were able to reproduce the structures of all TS studied within a maximum absolute deviation of 7%. The complex reaction mechanism was extended by three new low lying reaction channels. These are indirect water elimination from CH3OOH resulted formaldehyde, H2 elimination yielded methylene peroxide, and methanol and reactive triplet oxygen were formed via H-shift in the third channel. CHEAT1 protocol based on HEAT345-(Q) method is a robust, general, and cheap alternative for high accurate kinetic calculations.Show less >

Language :

Anglais

Audience :

Internationale

Popular science :

Non

Administrative institution(s) :

Université de Lille
CNRS

Collections :

• Physicochimie des Processus de Combustion et de l'Atmosphère (PC2A) - UMR 8522

Research team(s) :

PhysicoChimie de l'Atmosphère (PCA)

Submission date :

2018-11-27T14:24:54Z
2019-07-02T14:53:55Z
2019-07-03T10:09:05Z
2020-03-13T08:42:49Z