Spectroscopic Study of the Negative Corona Discharge in liquid andsupercritical 4He

摘要

Spectra of the corona discharge plasma in4 He have been investigated as a function of pressurebetween 0.1MPa and 10.4MPa and of the temperature from 4.2K to 7K.In liquid helium at 4.2K and0.1MPa,the analysis of the molecular singlet band d 1 ∑u + -b1∏g led to a rotational temperature of about350K.The blue shift and the broadening of the lines at 706.5nm (3s 3 S -2p 3 P)and 728nm (3s 1 S-2p 1 P),and the bands d 1 ∑u + →b 1 ∏g and d 3 ∑u + →b 3 ∏g have been determined for different pressures up to 4MPa.We have also investigated the spectra of corona discharge in supercritical gaseous helium at 6-7K.Theshift and the broadening of the triplet d 3 ∑u + →b 3 ∏g (639nm)transition in supercritical He is extracted from a numerical simulation of the spectrum observed.