Formations of negative ions in Sf6/N2 mixtures and their transport at atmospheric pressure

Formation of negative ions initiated by interaction of thermal electrons and in the corona discharge (CD) in N 2 with small admixture of SF 6 ; was studied using the ion mobility spectrometry- orthogonal acceleration time-of-flight mass spectrometry (IMS-oaTOF) at atmospheric pressure. The negative ions have been analyzed by the ion mobility spectrometry and mass spectrometry (IMS-MS) and two-dimensional spectra (2D IMS-MS) have been recorded. We discuss the mechanisms of the negative ion formation in the N 2 /SF 6 mixtures (0.003-0.018%) as well as the transport parameters of the ions in these mixtures. The values of the reduced ion mobilities of negative ions formed in these mixtures were determined (2.43 cm 2 /V s for HF 2 – (HF) n , 2.32 cm 2 /V s for NO 3 – (HF) n , 2.08 cm 2 /V s for SF 5 – , 2.01 cm 2 /V s for SOF 5 – , 2.00 for SOF 4 – 1.99 cm 2 /V s for SF 6 – , 1.83 cm 2 /V s for SOF 5 – (H 2 O) n and 1.73 for SOF 5 – (H 2 O) n (HF) m ). The assignment of the ion mobility peaks was performed on the basis of the 2D IMS-MS spectra.