Collision Energy Dependent Cross Section and Rotational Alignment of NO (A 2Σ+) in the Energy-Transfer Reaction of N2 (A3Σu+) + NO (X 2Π) → N2 (X 1Σg+) + NO (A 2Σ+)
Abstract:We have studied the collision energy dependent cross section and alignment of NO (A (2)Σ(+)) rotation in the energy-transfer reaction of N2 (A (3)Σ(u)(+)) + NO (X (2)Π) → N2 (X (1)Σ(g)(+)) + NO (A (2)Σ(+)) at the collision energy (E) region of 0.03-0.2 eV. NO (A (2)Σ(+)) emission in two linear polarization directions in the collision frame (parallel (∥) and perpendicular (⊥) with respect to the relative velocity vector (vR)) has been measured as a function of collision energy. NO (A (2)Σ(+)) rotation (J-vector… Show more
Comprehensive quantum chemical analysis with the usage of density functional theory and post-Hartree-Fock approaches were carried out to study the processes in the N2(A(3)Σu(+)) + CH4 and N2(A(3)Σu(+)) + C2H6 systems. The energetically favorable reaction pathways have been revealed on the basis of the examination of potential energy surfaces. It has been shown that the reactions N2(A(3)Σu(+)) + CH4 and N2(A(3)Σu(+)) + C2H6 occur with very small or even zero activation barriers and, primarily, lead to the formation of N2H + CH3 and N2H + C2H5 products, respectively. Further, the interaction of these species can give rise the ground state N2(X(1)Σg(+)) and CH4 (or C2H6) products, i.e., quenching of N2(A(3)Σu(+)) by CH4 and C2H6 molecules is the complex two-step process. The possibility of dissociative quenching in the course of the interaction of N2(A(3)Σu(+)) with CH4 and C2H6 molecules has been analyzed on the basis of RRKM theory. It has been revealed that, for the reaction of N2(A(3)Σu(+)) with CH4, the dissociative quenching channel could occur with rather high probability, whereas in the N2(A(3)Σu(+)) + C2H6 reacting system, an analogous process was little probable. Appropriate rate constants for revealed reaction channels have been estimated by using a canonical variational theory and capture approximation. The estimations showed that the rate constant of the N2(A(3)Σu(+)) + C2H6 reaction path is considerably greater than that for the N2(A(3)Σu(+)) + CH4 one.
Comprehensive quantum chemical analysis with the usage of density functional theory and post-Hartree-Fock approaches were carried out to study the processes in the N2(A(3)Σu(+)) + CH4 and N2(A(3)Σu(+)) + C2H6 systems. The energetically favorable reaction pathways have been revealed on the basis of the examination of potential energy surfaces. It has been shown that the reactions N2(A(3)Σu(+)) + CH4 and N2(A(3)Σu(+)) + C2H6 occur with very small or even zero activation barriers and, primarily, lead to the formation of N2H + CH3 and N2H + C2H5 products, respectively. Further, the interaction of these species can give rise the ground state N2(X(1)Σg(+)) and CH4 (or C2H6) products, i.e., quenching of N2(A(3)Σu(+)) by CH4 and C2H6 molecules is the complex two-step process. The possibility of dissociative quenching in the course of the interaction of N2(A(3)Σu(+)) with CH4 and C2H6 molecules has been analyzed on the basis of RRKM theory. It has been revealed that, for the reaction of N2(A(3)Σu(+)) with CH4, the dissociative quenching channel could occur with rather high probability, whereas in the N2(A(3)Σu(+)) + C2H6 reacting system, an analogous process was little probable. Appropriate rate constants for revealed reaction channels have been estimated by using a canonical variational theory and capture approximation. The estimations showed that the rate constant of the N2(A(3)Σu(+)) + C2H6 reaction path is considerably greater than that for the N2(A(3)Σu(+)) + CH4 one.
Comprehensive quantum chemical analysis with the usage of the second-order perturbation multireference XMCQDPT2 approach was carried out to study the processes in theThe energetically favorable reaction pathways have been revealed based on the exploration of potential energy surfaces. It has been shown that the reactions N 2 (A 3 Σ + u ) + H 2 and N 2 (A 3 Σ + u ) + H 2 O occur with small activation barriers and, primarily, lead to the formation of N 2 H + H and N 2 H + OH products, respectively. Further, the interaction of these species could give rise to the ground state N 2 (X 1 Σ + g ) and H 2 (or H 2 O) products, however, the estimations, based on RRKM theory and dynamic reaction coordinate calculations, exhibited that the N 2 (A 3 Σ + u ) + H 2 and N 2 (A 3 Σ + u ) + H 2 O reactions lead to the N 2 (A 3 Σ + u ) dissociative quenching predominately. Appropriate rate constants for revealed reaction channels have been estimated by using a canonical variational theory and capture approximation. Corresponding three-parameter Arrhenius expressions for the temperature range T = 300 − 3000 K were reported.
A new kinetic thermal nonequilibrium model for air plasma, considering vibrations of , and molecules in both the ground and electronically excited states in a state-to-state approach, was developed. The model treats in a consistent way the coupling of vibrational–electronic excitation of molecules and plasma chemical reactions as well as thermal nonequilibrium between translational degrees of freedom of electrons and heavy particles. The model was validated against the values of the radiation intensity of the and bands measured in the shock-tube experiments in an – mixture at shock wave speeds up to . Numerical analysis of thermally nonequilibrium processes in shock wave air plasma using the developed state-to-state model was conducted. It was shown that behind the shock front, a non-Boltzmann distribution over vibrational levels of , and molecules in both the ground and electronically excited states forms, but at the same time low vibration levels of these molecules are still populated in line with the local Boltzmann distribution with its own vibrational temperature. However, at extremely high shock wave velocities () disruption of the Boltzmann distribution of and molecules starts from vibrational levels with quantum numbers , so it is worth using the state-to-state consideration in such cases.
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