Theoretical Study of the Reactions of Methane and Ethane with Electronically Excited N2(A3Σu+)

Sharipov, Alexander S.; Loukhovitski, Boris I.; Starik, A. M.

doi:10.1021/acs.jpca.6b04244

Cited by 14 publications

(4 citation statements)

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“…These values of k rec are only half the values of the corresponding k′ for each isomer, but k′ and k rec are of the same order. Therefore, we consider that k′ and k rec in each isomer are almost the same value, and we conclude that the dissociation of xylene molecules are caused by the excitation transfer reaction [37] from N 2 A 3 + u to xylene molecules represented by their rate coefficients k′ determined by our present experiments.…”

Section: Determination Of Fundamental Coefficients Forsupporting

confidence: 55%

Collisional quenching of $\boldsymbol{{{{\rm N}}_{2}}({{{\rm A}}^{3}}\Sigma _{u}^{+})}$ by three xylene isomers and prevention of discharge current induced by film deposited on cathode by decomposion of xylene

Suzuki¹

2018

J. Phys. D: Appl. Phys.

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Determination of the effective lifetime of in N2 with an admixture of a small amount of xylene (dimethylbenzene C6H4(CH3)2) was carried out by waveform analysis of the transient current after turning off the UV light in a Townsend discharge. Xylene has three isomers (o-, m- and p-), and the collisional quenching rate coefficients of by these isomers were determined together with the diffusion coefficients of and the reflection coefficients of on an electrode surface. We found that the obtained collisional quenching rate coefficients of by o-, m- and p-xylene are considerably different as (2.3 ± 0.3) × 10−10, (4.4 ± 0.6) × 10−10 and (6.5 ± 0.9) × 10−10 cm3 s−1, respectively. During repeated measurements, we observed variations of the ionization process in the admixtures, which appeared as distorted transient current waveforms with fluctuation, making it impossible to continue the experiment to determine the three coefficients. The results suggest that the electron emission from the surface of the cathode is prevented by a deposited substance covering the cathode. This substance on the surface was identified as CHn (n = 1, 2, 3), which split from the benzene ring of the xylene molecules.

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Section: Determination Of Fundamental Coefficients Forsupporting

confidence: 55%

Collisional quenching of $\boldsymbol{{{{\rm N}}_{2}}({{{\rm A}}^{3}}\Sigma _{u}^{+})}$ by three xylene isomers and prevention of discharge current induced by film deposited on cathode by decomposion of xylene

Suzuki¹

2018

J. Phys. D: Appl. Phys.

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“…To additionally verify the accuracy of calculated values of E a + (a) and E a + (b) energy barriers, the compound G3MP2, G4MP2, and CBS-QB3 methods, based on a sequence of predefined ab initio molecular orbital calculations and involving special empirical corrections to ensure high target accuracy, were employed. Note that these composite techniques were chosen for comparative analysis because they had previously been proved to be effective in determining energy barriers on the excited PESs. ,,,, …”

Section: Resultsmentioning

confidence: 99%

“…Note that these composite techniques were chosen for comparative analysis because they had previously been proved to be effective in determining energy barriers on the excited PESs. 94,108,109,153,154 One can see that the use of modern higher-level methods in general leads to some decrease in the entrance energy barriers on the 2 A′ and 4 A′ PESs compared with early data by Walch and Jaffe. 17 with CASPT2 calculations 37 giving the lowest E a + (a) value [aside from the zero value obtained by Starik et al 44 during the plain CASSCF calculations with apparently insufficient (9,7) active space].…”

Section: Analysis Of the Nascent Energymentioning

confidence: 93%

Reaction of the N Atom with Electronically Excited O₂ Revisited: A Theoretical Study

2021

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The kinetics of the reaction of N with electronically excited O 2 (singlet a 1 Δ g and b 1 Σ g + states), potentially relevant for NO x formation in nonthermal air plasma, is theoretically studied using the multireference second-order perturbation theory. The corresponding thermodynamically and kinetically favored reaction pathways together with possible intersystem crossings are identified. It has been revealed that the energy barrier for the N + O 2 (a 1 Δ g ) → NO + O reaction is approximately twice the barrier height for the counterpart process with O 2 (X 3 Σ g − ). The molecular oxygen in the b 1 Σ g + state, in turn, proved to be even less reactive to atomic nitrogen than O 2 (a 1 Δ g ). Appropriate thermal rate constants for specified reaction channels are calculated by the variational transition-state theory incorporating corrections for the tunneling effect, nonadiabatic transitions, and anharmonicity of vibrations for transition states and reactants. The corresponding threeparameter Arrhenius expressions for the broad temperature range (T = 300−4000 K) are reported. At last, post-transition-state molecular dynamics simulations indicate that the N + O 2 (a 1 Δ g ) reaction produces vibrationally much colder NO molecules than the N + O 2 (X 3 Σ g − ) process.

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“…It is important to note that in the afterglow of a pure nitrogen plasma in a quartz tube, the concentrations of metastable molecules, N 2 (A 3 Σ + u ), and N( 2 P) and N( 2 D) atoms can be high [64][65][66][67][68] due to production mechanisms involving reactions with long-lived vibrational states N 2 (X 1 Σ + g , v 1). The electronically excited particles have high reaction rate constants with different hydrocarbons [69][70][71][72], so fast reactions with -CH 3 groups can take place on pore surfaces. These metastable particles may have a high probability of surface quenching [73], i.e.…”

Section: N Atomsmentioning

confidence: 99%

Damage to porous SiCOH low-k dielectrics by O, N and F atoms at lowered temperatures

Lopaev¹,

Zyryanov²,

Zotovich³

et al. 2020

J. Phys. D: Appl. Phys.

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Information on the degradation of porous organosilicate glasses (OSGs) by active radicals and atoms is of high importance for their integration as low-k dielectrics in the next generation of ultra large scale integration (ULSI) production. The films’ degradation is caused by depletion of coverage of the pore surface methyl. OSG samples with differing porosities and pore sizes were treated by O, N, and F atoms at lowered temperatures (down to −45 °С) downstream of O2, N2, and SF6 inductively coupled plasma discharges, respectively. It has been shown that lowering the temperature reduces film degradation. In the case of O atoms, this reduction is insignificant, while the effect is much more noticeable for F atoms. In addition, an accumulation of F atoms forms a fluorocarbon layer during F atom treatment. The accumulated fluorine can interact with surface Si atoms, giving rise to film etching. The film degradation under O and F atoms increases with pore size and porosity, due to deeper atom penetration. In the case of N atoms, even a small temperature reduction essentially decreases OSG degradation, while –CH3 modification is less clear in the cases of O and F atoms. Density functional theory and ab initio molecular dynamics simulations of reaction mechanisms show that atom reactions with surface Si–CH3 groups are the initial stages of OSG degradation. Subsequent mechanisms include branched reaction pathways with the formation, modification, and destruction of different surface groups. In the cases of O and F atoms, these reactions lead to the formation of HxCО and CFx bonds. For the direct reaction of N(4S) atoms with –СН3 groups, significant activation energy is required. Under downstream plasma conditions, –СН3 groups are destroyed in reactions with metastable particles, and first of all, with metastable atoms N(2D), N(2P) and molecules , which are also produced inside the pores in the surface recombination of nitrogen atoms.

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Theoretical Study of the Reactions of Methane and Ethane with Electronically Excited N₂(A³Σ_u⁺)

Cited by 14 publications

References 92 publications

Collisional quenching of $\boldsymbol{{{{\rm N}}_{2}}({{{\rm A}}^{3}}\Sigma _{u}^{+})}$ by three xylene isomers and prevention of discharge current induced by film deposited on cathode by decomposion of xylene

Collisional quenching of $\boldsymbol{{{{\rm N}}_{2}}({{{\rm A}}^{3}}\Sigma _{u}^{+})}$ by three xylene isomers and prevention of discharge current induced by film deposited on cathode by decomposion of xylene

Reaction of the N Atom with Electronically Excited O₂ Revisited: A Theoretical Study

Damage to porous SiCOH low-k dielectrics by O, N and F atoms at lowered temperatures

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Theoretical Study of the Reactions of Methane and Ethane with Electronically Excited N2(A3Σu+)

Cited by 14 publications

References 92 publications

Collisional quenching of $\boldsymbol{{{{\rm N}}_{2}}({{{\rm A}}^{3}}\Sigma _{u}^{+})}$ by three xylene isomers and prevention of discharge current induced by film deposited on cathode by decomposion of xylene

Collisional quenching of $\boldsymbol{{{{\rm N}}_{2}}({{{\rm A}}^{3}}\Sigma _{u}^{+})}$ by three xylene isomers and prevention of discharge current induced by film deposited on cathode by decomposion of xylene

Reaction of the N Atom with Electronically Excited O2 Revisited: A Theoretical Study

Damage to porous SiCOH low-k dielectrics by O, N and F atoms at lowered temperatures

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Theoretical Study of the Reactions of Methane and Ethane with Electronically Excited N₂(A³Σ_u⁺)

Reaction of the N Atom with Electronically Excited O₂ Revisited: A Theoretical Study