Spectral analysis of light emitted from streamers in chlorinated alkane & alkene liquids

We have studied the spectral light from fast positive and negative streamers in five chlorocarbon liquids under pulsed divergent field conditions (30 kV). Atomic lines and C₂ molecular Swan bands were observed, and with sufficient resolution to evaluate line and band-shapes. The characteristic broadening, shift and asymmetry of atomic lines varied significantly with the liquids, while differences between streamer polarities were comparatively small. Densities of electrons and neutrals have been deduced from broadening of atomic lines, atomic excitation temperatures from radiated intensity, and rotational and vibrational temperatures from the Swan bands.