In-situ Calibration for Electric Field Measurements in Glow-Discharge Plasmas by Laser-Induced Fluorescence Using the Optogalvanic Technique

We proposed and performed an in-situ calibration of electric field determination in glow-discharge plasmas based on the Stark effect, to relate ratios of laser-induced fluorescence (LIF) intensities (forbidden/allowed) with electric fields E, where accurate E values were measured by the laser optogalvanic (LOG) method. The results were compared with Bell Lab Group static calibration, and yielded 30% lower E value at a given fluorescence intensity. It is discussed, by the aid of solutions of rate equations for the LIF processes, that the present calibration is more accurate at higher electric field (E>100 V/mm) than that obtained by extrapolation of Bell Lab Group results at lower field (E<94.3 V/mm). Also, in the course of this comparison, the value of electric dipole moment for BCl was estimated to be µ=0.93±0.02 Debye.