Topchiev Institute of Petrochemical Synthesis, RAS, Moscow, Russia
K. von Haeften
Department of Physics and Astronomy, University of Leicester, UK pos Анотація:
Received December 1, 2010
The liquid 4He 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 He2 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 d3Σu+ – b3Πg molecular band. A positive corona was realized on a point anode for fewer radii of the electrode and larger voltage than in the negative corona. Electric currents in both negative and positive corona differ weakly. Spectral analysis of the radiation from the positive corona shows qualitative differences of spectral features of these discharges. The spectra observed in the positive corona have marked nonsymmetric shape. The asymmetric atomic and molecular spectra show an increased intensity of their long-length (red) wings.
PACS: 36.40.Mr Spectroscopy and geometrical structure of clusters; PACS: 71.35.Aa Frenkel excitons and self-trapped excitons; PACS: 73.20.–r Electron states at surfaces and interfaces; PACS: 78.40.–q Absorption and reflection spectra: visible and ultraviolet.
Key words: spectra, liquid normal helium, corona discharge.