Measurements of transport coefficients for lithium ions in argon and helium ions in helium with a drift-tube mass spectrometer

Abstract

A drift-tube mass spectrometer for precision measurements of transport coefficients for ions in gases is described. The apparatus has been used to determine the ratio D_T/ mu between the transverse diffusion coefficient and the mobility for He⁺ ions in the helium at 294 K and 150dr and the ratio D_L/ mu between the longitudinal diffusion coefficient and the mobility for Li⁺ ions in argon at 295 K and 400T/ mu for Li⁺ ions in argon at 294 K and 150<or=550Td, using the Townsend method. Good agreement was found between the present experimental results and recent calculations from at initio potentials.