Open AccessThe ultra- violet band of ammonia, and its occurrence the solar spectrum
Author(s) -
A. Fowler,
Christopher Gregory
Publication year - 1918
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.1918.0032
Subject(s) - spectral line , atmosphere (unit) , ammonia , chemistry , physics , optics , astrophysics , astronomy , meteorology , organic chemistry
A question of great interest in connection with the solar spectrum is that of the origin of the thousands of unidentified faint lines which were photographed and catalogued by Rowland. Some of these lines may possibly be identical with faint lines in metallic spectra which have not yet been completely tabulated, but in view of the presence of bands of cyanogen, carbon, and hydrocarbon, the possibility of the correspondence of most of them with band spectra of other substances should not be overlooked. As a contribution to this inquiry, the present investigation was undertaken primarily in order to determine whether Group P in the ultra-violet region of the solar spectrum might not be mainly due to the presence of ammonia in the absorbing atmosphere of the sun. Ammonia was already known to give a remarkable band in this region, having its greatest intensity near λ 3360, but existing records of the component lines were inadequate for comparison with the solar tables. Photographs were accordingly taken with instruments of various dispersions, ranging up to that of the third order of a 10 feet concave grating, a copper arc in an atmosphere of ammonia being employed as the source in the latter case. In view of the unusual appearance of the band, an attempt has also been made to elucidate the chief features of its structure.