Spectres continus moléculaires et atomiques d'émission du mercure

Abstract

Using the electrodeless discharge as an excitation method much information can be obtained about the mechanism of spectral emission. This discharge enables the successive emission of spectra, obtained simultaneously with any other excitation method. In this way the continuous spectrum of mercury vapour in the range 6400 Å–2200 Å was studied, using damped and undamped waves. Using undamped waves the following spectra were obtained: (1) the arc-lines of mercury. (2) continuous spectra: C I from 5800–4100 Å G II from 3650–3100 Å C III over the entire range studied. (3) unresolved band-spectra: S 1 from 5265–5015 Å S 2 from 4721–4491 Å S 3 from 4312–4132 Å Using damped waves: (1) arc and spark lines of mercury (2) continuous spectra C I and C II as mentioned above and C IV over the entire range studied like C III, but probably with a different emission-mechanism. A systematic study of these spectra (effect of vapour pressure, temperature, excitation voltage) confirmed previous results. Moreover, using undamped waves we observed: (1) The continuous spectrum C III which might be due to the coexistence in the same part of the discharge tube of two recombination-processes. (a) recombination of an ionized atom and an electron. (b) recombination of an ionized molecule and an electron. (2) Three diffuse band series, observed in the continuum C III, probably due to the transitions of the molecular states 6 1 S 0 + 7 1 D 2, 6 1 S 0 + 8 1 D 2, 6 1 S 0 + 9 1 D 2 to 6 1 S 0 + 6 1 P 1. The third series from 4312 to 4132 was mentioned already. It was possible to distinguish the molecular spectra C I and C II by their relative vertical position in the same spectrogram; the first time in our opinion that the excitation gradient in electrodeless discharge was used in the field of molecular spectra to separate the spectra of different excitation types.