Open AccessThe absorption spectrum of lithium vapour
Publication year - 1930
Publication title -
proceedings of the royal society of london. series a, containing papers of a mathematical and physical character
Language(s) - English
Resource type - Journals
eISSN - 2053-9150
pISSN - 0950-1207
DOI - 10.1098/rspa.1930.0161
Subject(s) - boiling point , materials science , absorption spectroscopy , lithium (medication) , analytical chemistry (journal) , optics , chemistry , physics , thermodynamics , medicine , chromatography , endocrinology
The absorption spectrum of lithium vapour has been previously studied under low dispersion by several workers. There are two main features of interest in it, the principal series, extending from the first line in the red at 6708 A. to a limit at 2299 A., and the band structures in the blue-green, 4500─5500 A. and in the red 6800─7700 A. The observation of the spectrum is attended by two principal difficulties: first, lithium has a high boiling point in the neighbourhood of 1400° C. at normal pressure, and it is strongly corrosive at high temperatures; secondly, the limit of the series has a very low wave-length, this fact rendering it very difficult to use a source not peculiarly rich in ultra-violet light for the transmission of continuous radiation through the vapour. Bevan, the first worker to publish any data* relating to this spectrum, heated lithium in a double-walled steel tube and used as illuminant a condensed cadmium spark; he used a quartz spectrograph and measured the wave-lengths of the first 41 members of the principal series with estimated error 0·2─0·3 A., deriving a Hick’s formula for their wave-numbers.