Experimental Ion Mobility measurements in Ne-CO2 and CO2-N-2 mixtures

Abstract

In this paper we present the experimental results for the mobility, K-0, of ions in neon-carbon dioxide (Ne-CO2) and carbon dioxide-nitrogen (CO2-N-2) gaseous mixtures for total pressures ranging from 8-12 Torr, reduced electric fields in the 10-25 Td range, at room temperature. Regarding the Ne-CO2 mixture only one peak was observed for CO2 concentrations above 25%, which has been identified as an ion originated in CO2, while below 25% of CO2 a second-small peak appears at the left side of the main peak, which has been attributed to impurities. The mobility values for the main peak range between 3.51 +/- 0.05 and 1.07 +/- 0.01 cm(2)V(-1)s(-1) in the 10%-99% interval of CO2, and from 4.61 +/- 0.19 to 3.00 +/- 0.09 cm(2)V(-1)s(-1) for the second peak observed (10%-25% of CO2). For the CO2-N-2, the time-of-arrival spectra displayed only one peak for CO2 concentrations above 10%, which was attributed to ions originated in CO2, namely CO2+ (CO2), with a second peak appearing for CO2 concentrations below 10%. This second peak, with higher mobility, was attributed to CO2+ ions. The mobility values of the main peak range between 2.11 +/- 0.04 and 1.10 +/- 0.03 cm(2)V(-1)s(-1) in the 1%-99% interval of CO2, while the second peak's from 2.26 +/- 0.02 and 1.95 +/- 0.04 cm(2)V(-1)s(-1) (1%-10% of CO2). The inverse of the mobility displays an aproximately linear dependence on the CO2 concentration in the mixture.