Atomic and molecular spectra of normal liquid 4He excited by corona discharges

Abstract

The liquid 4 He at fixed temperature 4.2 K and different pressures up to 8 MPa was excited by corona discharge of both negative and positive polarity. Emission of He I atomic lines and He 2 molecular bands are observed. In negative corona the lines spectra show a distinct blue-shift and line-broadening, which becomes stronger with the pressure increasing. The rotational structure of molecular bands is resolved at pressures (0.1-0.2) MPa. The blue shift of the Q-branch maximum at different pressures was observed. Rotational temperature of 900 K has been estimated for the