State-to-state N2(A 3Σ+u) energy-pooling reactions. I. The formation of N2(C 3Πu) and the Herman infrared system

Abstract

We have studied the formation of N2(C 3Πu, v=0–4) and the nitrogen Herman infrared system, v′=2,3, in energy pooling reactions between N2(A 3Σ+u, v′=0–1). Our results indicate rate coefficients of (1.5±0.4) and (1.5±0.5)×10−10 cm3 molecule−1 s−1 for formation of N2(C 3Πu, v′=0–4) from the energy pooling of two N2(A,v′=0) molecules and for a v′=0 and a v′=1 molecule, respectively. We did not see evidence of significant N2(C) formation in energy pooling between two N2(A,v′=1) molecules (k<5×10−11 cm3 molecule−1 s−1). N2(A,v′=0) energy pooling produces only v′=3 of the Herman infrared system with a rate coefficient of ≥(8.1±2.3)×10−11 cm3 molecule−1 s−1. Energy pooling between N2(A,v′=0) and N2(A,v′=1) produces only v′=2 of the Herman infrared system with a rate coefficient ≥(9.9±2.9)×10−11 cm3 molecule−1 s−1. Again, energy pooling between two N2(A,v′=1) molecules results in no significant contributions to the Herman infrared system. The participation of N2(A) vibrational levels ≥2, however, does result in excitation of the lower-lying vibrational levels of the Herman infrared system.

Plasma preconditioning and the role of elevated vibrational temperature in production of excited N2 vibrational distributions

“…Regarding the two energy pooling processes, (1) N2(A) + N2(A ) -• N2(B ) + N2(X ) and (2) N2(V) + N2(A)-• N2(X) + N2(B), we do not consider our observations during the current pulse to be consistent with these reactions. These processes were discussed by Hays and Oskam [1973] and others, the most recent work being a series of articles by Piper [1988aPiper [ , b, 1989]. In Piper's [1988a, b] study considering the first process he sees strong bands of the Herman infrared (HIR) system occurring throughout the 5500-8500 A region.…”

Influence of ambient air on the flowing afterglow of an atmospheric pressure Ar/O2 radiofrequency plasma

“…Possible pathways for the excitation of N 2 molecules to the C 3 P u electronic state include: electron impact excitation from lower excited states or from the X 1 R þ g ground state, energy pooling reactions between N 2 (A 3 R þ u ) molecules, 38 cascade transitions from higher excited states, and collision induced energy transfer between Ar metastable atoms and N 2 (X 1 R þ g ) molecules. 39 The electron density and Ar metastable concentration determined from a two-dimensional fluid model on a very similar plasma source (the excitation frequency is 13.56 MHz, a pure Ar discharge is considered, and there is no inlet distributor under the grounded electrode) lie in the range 10 10 -10 11 cm À3 and 10 9 -10 10 cm À3 , respectively.…”

Determination of N and O‐atoms and N2 (A) Metastable Molecule Densities in the Afterglows of N2‐H2, Ar‐N2‐H2 and Ar‐N2‐O2 Microwave Discharges

“…From the kinetics reactions reported in [17], it is considered that the N 2 2 nd positive system in the early afterglow is produced by the following dominant reactions :…”