Determination of mobility and diffusion coefficients of Ar+ and Ar2+ ions in argon gas

Autor: William Pfalzgraff, Aaron D. Trout, Michelle Cordier, Delenn Fingerlow, Larry A. Viehland, J. Dashdorj
Rok vydání: 2020
Předmět:
Zdroj: International Journal for Ion Mobility Spectrometry. 23:143-151
ISSN: 1865-4584
1435-6163
Popis: It has recently been shown that accurate theoretical calculations can be used to calibrate a drift-tube mass spectrometer (DTMS) to measure gaseous ion mobilities accurate to within 0.6%. Here we present a new method for calibrating a DTMS instrument to obtain diffusion coefficients parallel to the electric field which are accurate to within 8%. This method is developed and verified by consideration of He+ (2S1/2) ions in He. We apply these techniques to determine transport coefficients for Ar+(2P3/2) and Ar2+ (3P2,1,0) ions in Ar gas at 300 K, with results given as a function of E/N, the ratio of electrostatic field strength to gas number density, in the range 30–210 Td. The measured mobilities are accurate within 0.8%; for Ar+ they agree within 1.5% with Monte Carlo simulations, and for both the cations and dications they are in excellent agreement with previous measurements. Our method gives new diffusion coefficients that agree within 5% with quantum Monte Carlo calculations.
Databáze: OpenAIRE
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