SELECTIVE AND TIME-RESOLVED FOURIER TRANSFORM ION SPECTRA.

Abstract

This paper illustrates some aspects of the work begun at LPPM in the field of Fourier Transform Ion Spectroscopy. Double-modulation and time-resolved emission FT spectra of molecular ions, created in glow discharges, are presented. The processing of first derivative-type selective $lineshapes^{a}$ is discussed. Results aiming at characterizing the transport properties and the abundance of ions in plasmas are reported. As an illustration, the quantum dependence of the average mobility of $ArH^{+}$ in an Ar/He mixture in an inhomogeneous electric field has been investigated from Doppler-shifts $measurements^{b}$. This fact demonstration extends to wide-band spectroscopy the measurements pioneered by Haese, Pan, and $Oka^{c}$ with diode-lasers, in similar source conditions. Spectroscopic means can now provide high quality state-resolved plasma characterization, as proven with lasers, in homogeneous electric fields, for instance in Leone's $group^{d}$. The determination of the rovibrational intensities of the $\Delta v=1$ sequence of $ArH^{+}$ has been undertaken. First attempts to observe ionic species in C, N, H containing electrical discharges are also reported.