Theoretical study on the singlet and triplet potential energy surfaces of NH (X3Σ−) + HCNO reaction

Jia, Xiujuan; Li, Sha; Yu, Yanbo; Wang, Rongshun; Pan, Xiumei

doi:10.1007/s00214-009-0707-9

Cited by 3 publications

(5 citation statements)

References 24 publications

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“…Later, Grußdorf et al [16] reported that the dominant channel is HCNO + H, accounting for about 84%. The physicochemical properties of HCNO, and its reactions with various species present in hydrocarbon combustion such as H-and O-atoms, HO x radicals, and other reactive species have been investigated [3,[17][18][19][20][21][22][23][24][25][26][27][28][29]. Theoretical studies showed that there are two main mechanisms for the reactions of HCNO, i.e.…”

Section: Introductionmentioning

confidence: 99%

Mechanism and kinetics for the reaction of fulminic acid, HCNO, with an amino radical, NH2

Nguyen

Nguyễn

Vereecken

2018

Combustion and Flame

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The reaction of fulminic acid, HCNO, with NH 2 radicals was studied using quantum chemical and theoretical kinetic methodologies. B3LYP/6-311++G(3df,2p) calculations combined with CCSD(T) energy calculations at the basis set limit reveal a complex potential energy surface, where only two entrance channels contribute significantly to the product formation. Transition state theory and RRKM master equation calculations find a rate coefficient ranging from 7.2  10-12 cm 3 molecule-1 s-1 at room temperature, to > 1 10-10 cm 3 molecule-1 s-1 at 3000 K. Despite a reduced efficiency in product formation due to fast redissociation of the adducts to the reactants at high temperatures, the title reaction can thus be an efficient sink for HCNO at combustion temperatures in nitrogen-rich environments. At 1 bar and below, H 2 NCO + NO is the dominant product, with H 2 NCN + OH and HCN + NHOH contributing weakly. This work presents rate coefficients and product distributions for the temperature range 300-3000K, and pressure range of 10-3 to 10 3 bar; a brute-force error analysis examines the expected uncertainty interval for these predictions.

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Section: Introductionmentioning

confidence: 99%

Mechanism and kinetics for the reaction of fulminic acid, HCNO, with an amino radical, NH2

Nguyen

Nguyễn

Vereecken

2018

Combustion and Flame

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“…Although we are aware of some theoretical studies for HNNCHO, − neither HNNCHO nor HNNCHS was observed experimentally earlier. These novel molecules can be important as being reactive intermediates in organic chemistry and they are also potential astrochemical species.…”

Section: Discussionmentioning

confidence: 87%

Photochemical Formation of Diazenecarbaldehyde (HNNCHO) and Diazenecarbothialdehyde (HNNCHS) in Low-Temperature Matrices

et al. 2018

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The photochemical decomposition of 1,2,4-oxadiazole-3,5-diamine and 1,2,4-thiadiazole-3,5-diamine was investigated in low-temperature Ar and Kr matrixes at different wavelengths. The analysis of matrix-isolation infrared (MI-IR) spectra aided by high-level quantum chemical computations showed not only that these photochemical reactions yield [NH, C, N, X] (X = O, S) isomers but also that the bands of a novel, formerly unobserved species were observed. The comparison of computed IR spectra of potential products with the observed spectra suggests that these species are the diazenecarbaldehyde (HNNCHO) and diazenecarbothialdehyde (HNNCHS). Neither of the reactive HNNCHO and HNNCHS molecules was observed experimentally before. Both molecules are identified in the matrix as a complex with the other photoproduct, NHCN. Comparison of the present experiments with former photochemical experiments on 1,2,5-oxadiazole-3,4-diamine and 1,2,5-thiadiazole-3,4-diamine and the analysis of the rate of formation of the different photoproducts indicate that HNNCHO and HNNCHS are formed in a different reaction path than HNNCX and HNC(NX) (X = O, S), and not by photoisomerization from these latter products.

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“…Structural parameters of T0/1 at the B3LYP/6-311++G(3df,2p) level are in good agreement with those derived by various wavefunction methods including MP2/6-311++G(3df,2p) and CASSCF/6-311++G(d,p) (see Figure 3). The H─C (1.065 Å), C─N (1.170 Å), N─O (1.199 Å), bond lengths of HCNO group in T0/1 computed by B3LYP/6-311++G(3df,2p) are close to 1.063 Å (H─C), 1.141 Å (C─N), and 1.202 Å (N─O) at the MP2/6-311++G(3df,2p) level, as well as 1.063 Å (H─C), 33 IRC calculations show that T0/1 connects the reactants to IS1; the transition state T0/1 has the unique imaginary frequency at 250i cm -1 and the spin expectation values for T0/1 and IS1, < S 2 > ≈ 0.77 and 0.76, respectively, show that spin contamination is negligible. T1 diagnostic values in Table S5 providing a description of the multi-reference character in the wave function are less than the critical values 0.020 and 0.045 for the singlet and doublet species, respectively, indicating that the wave functions are dominated by a single determinant and the CCSD(T) method is reliable.…”

Section: Entrance Channelsmentioning

confidence: 81%

“…32 These results are similar to reactions of HCNO with other radicals such as OH, 3 NH, and so on. 3,14,[32][33][34] Of the four entrance transition structures, the addition of CH 3 to the HCNO carbon atom is expected to be the dominant channel, owing to its low entrance barrier as compared with those of the other channels. H-abstraction begins to contribute only at high temperatures only.…”

Section: Entrance Channelsmentioning

confidence: 99%

“…A number of reactions of HCNO with small radicals such as OH, NH (singlet and triplet), CN, and OCN were investigated either experimentally or theoretically. 3,[14][15][16][17][29][30][31][32][33][34] In general, theoretical results showed that the initial association to the C-atom in HCNO is a major entrance channel leading to the dominant products, and that this process can occur via either a barrierless process or a well-defined transition structure. For example, HCNO reacts with O( 3 P), CN, NCO in barrierless processes to form HC(X)NO, in which X is the reactant species.…”

Section: Introductionmentioning

confidence: 99%

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Prediction of the product channels in the reaction of the methyl radical with fulminic acid

Nguyễn

Nguyen

2020

Int J of Chemical Kinetics

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The reaction of CH 3 + HCNO was theoretically studied by both density functional theory and molecular orbital calculations and analyzed by quantum statistical methods. The potential energy surface was constructed at the UCCSD(T)//B3LYP/6-311++G(3df,2p) + ZPE level. Four entrance channels are opened relating to the interaction of the CH 3 radical with each of the four atoms of the HCNO molecule, giving rise to 18 different product sets. The predicted geometries and heats of reaction are in good agreement with available experimental data. The major pathways involve addition of CH 3 to the C atom of HCNO with a small energy barrier of ∼4 kcal/mol forming both Z and E-HC(CH 3)NO (IS1/IS1b) intermediates lying 45 or 44 kcal/mol, respectively, below the reactants. The nascent intermediates can collisionally be deactivated and subsequently decomposed into H + CH 3 CNO or isomerized prior to decomposition giving other products. Kinetics calculations covering the temperature range of 400-2500 K, under pressures of 7.6 × 10-1 to 7.6 × 10 5 Torr for N 2 , He, and Ar as the third bodies show that at 760 Torr N 2 , the adducts including both IS1 and IS1b are the major products at temperature below 600 K, whereas H + CH 3 CNO and CNO + CH 4 are the major products at T ≥ 1500 K. The total high-pressure rate coefficient can well be expressed by the following three-parameter equation: k(T) = 7.75 × 10-16 T 1.69 exp (−1480 K/T) cm 3 molecule-1 s-1 .

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Theoretical study on the singlet and triplet potential energy surfaces of NH (X3Σ−) + HCNO reaction

Cited by 3 publications

References 24 publications

Mechanism and kinetics for the reaction of fulminic acid, HCNO, with an amino radical, NH2

Mechanism and kinetics for the reaction of fulminic acid, HCNO, with an amino radical, NH2

Photochemical Formation of Diazenecarbaldehyde (HNNCHO) and Diazenecarbothialdehyde (HNNCHS) in Low-Temperature Matrices

Prediction of the product channels in the reaction of the methyl radical with fulminic acid

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