DEPARTURES FROM THERMODYNAMIC EQUILIBRIUM IN A HELIUM R.F. DISCHARGE.
Abstract
Measurements by Crosswhite and Dieke (Am. Inst. Physics Handbook, 1957) of the visible lines of neutral helium emitted in a discharge that was excited by r.f. fields of 15 Mc frequency were used to deduce the population ratios of the various excited states. It is found that the highest states are strongly underpopulated with respect to lower excited states, that there is no significant difference between triplet and singlet populations, and that for any given principal quantum number the S state is highly overpopulated with respect to P and D states. It is concluded that the excitation takes place from the ground state, and that observed population ratios may possibly be used to predict the electron distribution function and/or the existence and amplitude of threshold resonances in the excitation cross-sections. Finally, it is pointed out that a discharge of the type discussed may act as a laser in a variety of spectral lines. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1965
- Accession Number
- AD0621703
Entities
People
- B. B. Chakraborty
- Linda Öster
Organizations
- Yale University