Experimental Measurement of H3+/H5+ and D3+/D5+ mobilities in their parent gases

The experimental study of the reduced mobility K-0 of the molecular ions H-3(+)/H-5(+) in H-2 and D-3(+)/D-5(+) in D-2 was carried out using a recently developed technique, that uses a Xe VUV flash lamp and a Gaseous Electron Multiplier (GEM) microstructure with a CsI deposit to produce the molecular ions by electron avalanche ionization. For both gases, the K-0 values were obtained at room temperature (295 K) and at pressures from 5 to 50 Torr for uniform reduced electric fields E/N from 4 to 40 Td. The reduced mobility derived from the measurements is an average of the K-0 value of the two molecular ions, and for the H-3(+) and H-5(+) ions is 11.1 cm(2)V(-1)s(-1) while for D-3(+) and D-5(+) it ranges from 8.5 to 7.8 cm(2)V(-1)s(-1), for pressure from 5 to 50 Torr. A discussion of the obtained results is presented.