Electron attachment and negative ion-molecule reactions in nitrous oxide

Abstract

The negative ions formed in NzO and NzO+O2 mixtures have been studied in the gas phase using a drift tube and mass filter. Gas pressures were in the Torr range, and reduced fields were varied between lo-'' and V cm2 molecule-'. The observed ion spectrum was found to be governed by the following reactions, with their associated thermal rate constants : e+N20+N2+0-, 0-+N20-+NO-+N0,NO-+N20-+N20+NO+e, kll = (6.0+ 1.0) x 10-l2 cm3 molecule-' s-'The rates of reactions (5), (6) and (1 1) were weak functions of reduced field. In no experiment was any evidence found for the existence of a long-lived N20ion.Nitrous oxide is used widely in radiation chemistry as an electron scavenger.I Its action has been interpreted in terms of the reaction :

Radiolysis of liquid nitrous oxide

“…In particular, Parks could not detect a long-lived N20ion, and at high nitrous oxide pressures Oions reacted rapidly to form N2O2™. 15 The corresponding liquid-phase mechanism might be as follows (mechanism I).…”

Evaluation of the removal efficiency of organic impurities by ECR plasma based on the ATR-FTIR analysis

“…Because of the fact that excited hydrogen atoms generated in H 2 plasma have relatively small molecular weights and low energies, organic contaminants cannot be easily removed by sputter-off. It is reported (9] that the hydrogen ion bombardment (sputter-oft) has hardly an influence on the etching of silicon oxides. Therefore, it is likely that the cleaning mechanism is not sputteroff, but lift-off following the chemical reaction between the chemically reactive species and organic contaminants.…”

On the paradigm

“…What do the experiments tell us about the trinitrogen dioxide anion? N 3 O À 2 was first observed nearly forty years ago by Moruzzi and Dakin [11] who conjectured its appearance as the intermediate state in the reaction of NO À with N 2 O having the lifetime of 4 • 10 À7 s. Four years later, Parkes [12] observed N 3 O À 2 as the product of the same reaction 'buffered' either by CO 2 , or Ar, or another N 2 O molecule:…”