ArH+ near 5 mu m with high resolution double modulation FTS

High resolution double modulation Fourier Transform Spectroscopy (FTS) is d emonstrated for the first time, It is applied to velocity modulation experi ments. Lines emitted from ions are successfully selected. The Delta v = 1 s equence of the ArH+ ions is recorded up to the 7-6 vibrational transition. Preliminary measurements of the Doppler-shifts show no vibrational effects from the Delta v = 1 sequence vibrational bands and most likely no vibratio nal state to-state dependence of the ArH+ ion mobility, (C) 1999 Elsevier S cience B.V. All rights reserved.