Energetics and molecular dynamics of the reaction of HOCO with HO 2 radicals

Hua Gen Yu, Gabriella Poggi, Joseph S. Francisco, James Muckerman

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The energetics of the reaction of HOCO with HO2 have been studied using the quadratic configuration interaction with single and double excitations (QCISD(T)) method and a large basis set on the singlet and triplet potential energy surfaces of the system. The results show that the ground-state O2 +HOC (O) H products can be produced by a direct hydrogen abstraction via a transition state with a small barrier (1.66 kcal/mol) on the lowest triplet surface. A similar hydrogen abstraction can occur on the singlet electronic surface, but it leads to the singlet O2 (a1 Δ) and HOC(O)H. On the singlet surface, a new stable intermediate, HOC(O)OOH, hydroperoxyformic acid, has been found. This intermediate is formed by the direct addition of the terminal oxygen atom in HO2 onto the carbon atom in HOCO in a barrierless reaction. The HOC(O)OOH intermediate may dissociate into either the CO2 + H2 O2 or CO3 + H2 O products through elimination reactions with four-center transition states, or into HOC (O) O+OH through an O-O bond cleavage. The heat of formation of HOC(O)OOH is predicted to be -118.9±1.0 kcal/mol. In addition, the dynamics of the HO2 +HOCO reaction have been investigated using a scaling-all correlation couple cluster method with single and double excitation terms (CCSD) on the singlet potential energy surface. Reaction mechanisms have been studied in detail. It was found that the direct and addition reaction mechanisms coexist. For the addition mechanism, the lifetime of the HOC(O)OOH intermediate is predicted to be 880±27 fs. At room temperature, the calculated thermal rate coefficient is (6.52±0.44) × 10-11 cm3 molecule-1 s-1 with the product branching fractions: 0.77 (CO2 + H2 O2), 0.15 (HOC (O) O+OH), 0.056 (CO3 + H2 O), 0.019 (O2 (a1 Δ) +HOC (O) H), and 0.01 (O2 (X 3 ) +HOC (O) H).

Original languageEnglish
Article number214307
JournalJournal of Chemical Physics
Volume129
Issue number21
DOIs
Publication statusPublished - 2008

Fingerprint

Molecular dynamics
Potential energy surfaces
molecular dynamics
Hydrogen
Atoms
Addition reactions
Ground state
Carbon
products
potential energy
Oxygen
Molecules
Acids
heat of formation
hydrogen
configuration interaction
excitation
cleavage
elimination
oxygen atoms

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Energetics and molecular dynamics of the reaction of HOCO with HO 2 radicals. / Yu, Hua Gen; Poggi, Gabriella; Francisco, Joseph S.; Muckerman, James.

In: Journal of Chemical Physics, Vol. 129, No. 21, 214307, 2008.

Research output: Contribution to journalArticle

Yu, Hua Gen ; Poggi, Gabriella ; Francisco, Joseph S. ; Muckerman, James. / Energetics and molecular dynamics of the reaction of HOCO with HO 2 radicals. In: Journal of Chemical Physics. 2008 ; Vol. 129, No. 21.
@article{7eb8543264694145affcb7a9142abdb6,
title = "Energetics and molecular dynamics of the reaction of HOCO with HO 2 radicals",
abstract = "The energetics of the reaction of HOCO with HO2 have been studied using the quadratic configuration interaction with single and double excitations (QCISD(T)) method and a large basis set on the singlet and triplet potential energy surfaces of the system. The results show that the ground-state O2 +HOC (O) H products can be produced by a direct hydrogen abstraction via a transition state with a small barrier (1.66 kcal/mol) on the lowest triplet surface. A similar hydrogen abstraction can occur on the singlet electronic surface, but it leads to the singlet O2 (a1 Δ) and HOC(O)H. On the singlet surface, a new stable intermediate, HOC(O)OOH, hydroperoxyformic acid, has been found. This intermediate is formed by the direct addition of the terminal oxygen atom in HO2 onto the carbon atom in HOCO in a barrierless reaction. The HOC(O)OOH intermediate may dissociate into either the CO2 + H2 O2 or CO3 + H2 O products through elimination reactions with four-center transition states, or into HOC (O) O+OH through an O-O bond cleavage. The heat of formation of HOC(O)OOH is predicted to be -118.9±1.0 kcal/mol. In addition, the dynamics of the HO2 +HOCO reaction have been investigated using a scaling-all correlation couple cluster method with single and double excitation terms (CCSD) on the singlet potential energy surface. Reaction mechanisms have been studied in detail. It was found that the direct and addition reaction mechanisms coexist. For the addition mechanism, the lifetime of the HOC(O)OOH intermediate is predicted to be 880±27 fs. At room temperature, the calculated thermal rate coefficient is (6.52±0.44) × 10-11 cm3 molecule-1 s-1 with the product branching fractions: 0.77 (CO2 + H2 O2), 0.15 (HOC (O) O+OH), 0.056 (CO3 + H2 O), 0.019 (O2 (a1 Δ) +HOC (O) H), and 0.01 (O2 (X 3 ) +HOC (O) H).",
author = "Yu, {Hua Gen} and Gabriella Poggi and Francisco, {Joseph S.} and James Muckerman",
year = "2008",
doi = "10.1063/1.3028052",
language = "English",
volume = "129",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics Publising LLC",
number = "21",

}

TY - JOUR

T1 - Energetics and molecular dynamics of the reaction of HOCO with HO 2 radicals

AU - Yu, Hua Gen

AU - Poggi, Gabriella

AU - Francisco, Joseph S.

AU - Muckerman, James

PY - 2008

Y1 - 2008

N2 - The energetics of the reaction of HOCO with HO2 have been studied using the quadratic configuration interaction with single and double excitations (QCISD(T)) method and a large basis set on the singlet and triplet potential energy surfaces of the system. The results show that the ground-state O2 +HOC (O) H products can be produced by a direct hydrogen abstraction via a transition state with a small barrier (1.66 kcal/mol) on the lowest triplet surface. A similar hydrogen abstraction can occur on the singlet electronic surface, but it leads to the singlet O2 (a1 Δ) and HOC(O)H. On the singlet surface, a new stable intermediate, HOC(O)OOH, hydroperoxyformic acid, has been found. This intermediate is formed by the direct addition of the terminal oxygen atom in HO2 onto the carbon atom in HOCO in a barrierless reaction. The HOC(O)OOH intermediate may dissociate into either the CO2 + H2 O2 or CO3 + H2 O products through elimination reactions with four-center transition states, or into HOC (O) O+OH through an O-O bond cleavage. The heat of formation of HOC(O)OOH is predicted to be -118.9±1.0 kcal/mol. In addition, the dynamics of the HO2 +HOCO reaction have been investigated using a scaling-all correlation couple cluster method with single and double excitation terms (CCSD) on the singlet potential energy surface. Reaction mechanisms have been studied in detail. It was found that the direct and addition reaction mechanisms coexist. For the addition mechanism, the lifetime of the HOC(O)OOH intermediate is predicted to be 880±27 fs. At room temperature, the calculated thermal rate coefficient is (6.52±0.44) × 10-11 cm3 molecule-1 s-1 with the product branching fractions: 0.77 (CO2 + H2 O2), 0.15 (HOC (O) O+OH), 0.056 (CO3 + H2 O), 0.019 (O2 (a1 Δ) +HOC (O) H), and 0.01 (O2 (X 3 ) +HOC (O) H).

AB - The energetics of the reaction of HOCO with HO2 have been studied using the quadratic configuration interaction with single and double excitations (QCISD(T)) method and a large basis set on the singlet and triplet potential energy surfaces of the system. The results show that the ground-state O2 +HOC (O) H products can be produced by a direct hydrogen abstraction via a transition state with a small barrier (1.66 kcal/mol) on the lowest triplet surface. A similar hydrogen abstraction can occur on the singlet electronic surface, but it leads to the singlet O2 (a1 Δ) and HOC(O)H. On the singlet surface, a new stable intermediate, HOC(O)OOH, hydroperoxyformic acid, has been found. This intermediate is formed by the direct addition of the terminal oxygen atom in HO2 onto the carbon atom in HOCO in a barrierless reaction. The HOC(O)OOH intermediate may dissociate into either the CO2 + H2 O2 or CO3 + H2 O products through elimination reactions with four-center transition states, or into HOC (O) O+OH through an O-O bond cleavage. The heat of formation of HOC(O)OOH is predicted to be -118.9±1.0 kcal/mol. In addition, the dynamics of the HO2 +HOCO reaction have been investigated using a scaling-all correlation couple cluster method with single and double excitation terms (CCSD) on the singlet potential energy surface. Reaction mechanisms have been studied in detail. It was found that the direct and addition reaction mechanisms coexist. For the addition mechanism, the lifetime of the HOC(O)OOH intermediate is predicted to be 880±27 fs. At room temperature, the calculated thermal rate coefficient is (6.52±0.44) × 10-11 cm3 molecule-1 s-1 with the product branching fractions: 0.77 (CO2 + H2 O2), 0.15 (HOC (O) O+OH), 0.056 (CO3 + H2 O), 0.019 (O2 (a1 Δ) +HOC (O) H), and 0.01 (O2 (X 3 ) +HOC (O) H).

UR - http://www.scopus.com/inward/record.url?scp=57349166080&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=57349166080&partnerID=8YFLogxK

U2 - 10.1063/1.3028052

DO - 10.1063/1.3028052

M3 - Article

C2 - 19063561

AN - SCOPUS:57349166080

VL - 129

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 21

M1 - 214307

ER -