Vibrationally resolved NO dissociative excitation cross sections by electron impact

Abstract

A theoretical investigation of the dissociative excitation by electron impact on the NO molecule is presented, aiming to make up for the lack of data for this process in the literature. A full set of vibrationally-resolved cross sections and corresponding rate coefficients are calculated using the Local-Complex-Potential approach and five resonant states of NO − . PACS numbers: xxxxxNitric oxide (NO) molecule is one of the minor components of terrestrial atmosphere. Generated in atmospheric plasma from chemical reactions of nitrogen with oxygen, NO and its radicals are very important in many industrial technologies [1][2][3][4][5] and play a key role in the combustion of fossil fuels [6,7]. Of the nitrogen oxide compounds, the so-called NOx gasses, the NO molecule has the greater impact on environment and on pollution caused by human activities [8,9].In order to make kinetic plasma models involving nitric oxide, many sets of molecular data [10][11][12], spectroscopic properties [13][14][15] and reaction rate coefficients [16][17][18][19] are available in the literature but, in spite of its importance, none of them provide complete data on electron impact dissociation. More specifically, rate constants for electron-NO reactions, both theoretical [14,[20][21][22] and experimental [23][24][25][26][27], exist only for vibrational excitation and dissociative electron attachment processes at low-energy. A recent compilation of all the known electron collision cross sections is given by Song et al. [16].To fill this gap, we present calculations -based on the formalism used previously [20] -of vibrational state resolved cross sections and the corresponding rate coefficients for dissociative excitation (DE) of NO by electron impact, i.e.:We consider electron collision energies where numerous NO − resonances exist, direct dissociation is negligible and the DE reaction is dominated by resonant processes [28,29]. Our aim is to cover a large range of incident electron energies, so we take into account five resonance states of NO − : the three low-lying states of 3 Σ − , 1 Σ + and 1 ∆ symmetries and two higher ones, with 3 Π and 1 Π symmetry, which lie close to the NO dissociation threshold. In the following, we number these resonances by r = 1, . . . , 5, respectively. The vibrational excited states of which converge on the N( 4 S) + O( 3 P) dissociation limit of Eq. (1), due to their symmetry, have small oscillator strengths and short lifetimes [10,30,31] so their influence on the DE process can be neglected. NO is a stable, open-shell molecule with a 2 Π ground electronic state, and a very accurate theoretical treatment of the electron-NO scattering therefore needs to take into account the spin-dependence of the process. However, the spin-orbit coupling effects are only important at very low energies [23] and, consequently, in the following we will neglect them.We start by briefly describing the theoretical model used to calculate the cross sections for the process (1), restricting ourselves to the major equations of the Lo...

Data Needs for Modeling Low-Temperature Non-Equilibrium Plasmas: The LXCat Project, History, Perspectives and a Tutorial

“…The Laporta database is a compilation of vibrationally resolved cross-sections for electron-molecule scattering based on R-Matrix calculations. It currently contains data for vibrationally resolved dissociative excitation and attachment for the NO [129,130] and O 2 [131] molecules.…”

Plasma Modeling and Prebiotic Chemistry: A Review of the State-of-the-Art and Perspectives

“…In recent years, motivated by the great importance of CO, CO , CO and NO molecules in astrophysics, aerospace and laser technologies, great improvements, theoretically and experimentally, in the quantitative understanding of the reactivity of these species in a weakly-ionized plasma have been achieved. Figure 8 summarizes the results for cross sections by electron impact for CO [ 100 , 101 ] and NO [ 102 , 103 ] molecules obtained with the LCP method, for CO [ 104 ] molecular ion obtained in the MQDT framework and for experimental data for the CO molecule [ 105 ].…”

“… Compilation of state-resolved cross sections by electron-impact: ( a ) electron-CO [ 100 , 101 ]; ( b ) electron-CO [ 105 ]; ( c ) electron-CO [ 104 ]; ( d ) electron-NO [ 102 , 103 ]. Processes of: Vibrational Excitation (VE); Dissociative Attachment (DA); Dissociative Recombination (DR); Dissociative Excitation (DE).…”

Dissociative electron attachment cross sections for ro-vibrationally excited NO molecule and N- anion formation

“…In our recent paper [1] we produced theoretical cross sections for the dissociative excitation of the nitric oxide (NO) molecule by electron impact. In order to supply further data for the non-equilibrium plasma modeling, and based on the same molecular data, in this letter we extend the calculations to its dissociative electron attachment (DA).…”

“…Since the excited electronic states of nitrogen atoms as well as its negative ion are unstable they undergo decays toward the ground state N( 4 S): in the plasma, the reaction DA2 will be followed by detachment process by electron emission for N − [33] and DA3 channel will be followed by radiative decay to N( 2 D). As specified in [1], in order to cover a large energy range for the incident electron, we take into account five resonant electronic states of NO − : three low-lying -i.e. of 3 Σ − , 1 Σ + and 1 ∆ symmetries -and two higher -of 3 Π and 1 Π symmetries -close to the NO dissociation threshold.…”