‎"RYDBERG, J.R. - ANNOUNCING ""RYDBERG'S CONSTANT"".‎
‎Sur la constitution des spectres linéaires des éléments chimiques.‎

‎(Paris, Gauthier-Villars), 1890. 4to. No wrappers. In: ""Comptes Rendus Hebdomadaires des Séances de L'Academie des Sciences"", Tome 110, No 8. Pp. (369-) 428. (Entire issue offered). Rydberg's paper: pp. 394-97.‎

Reference : 48905

‎In this paper Rydberg announced his formula, later termed ""Rydberg's Constant - the paper being a shortened version of the larger paper, published at the same time in Kungliga Vetenskaps Akademiens Handlinger with the title ""Recherches sur la constitution des spectres d’émission des éléments chimiques"" - in which he stated as a fundamental principle that ""in the spectra of all the elements analyzed and so far thjere are series of rays whose wavelenghts or wave numbers are functions of consecutive integral numbers"". The equation became an importent inspiration for the development of quantum theory and for the formulation of quantum states by Niels Bohr. Bohr’s view provided an immediate interpretation of the combination principle by identifying each Rydberg spectral term multiplied by hc (Planck’s constant times the speed of light) with the energy of an allowable stationary state of the atom. The difference between two such states equaled the energy in the light quantum emitted in the transition from a higher allowable atomic-energy state to a lower one.""His major spectral work, ""Recherches sur la constitution des spectres d’émission des éléments chimiques"", published in 1890, mapped out Rydberg’s total approach with remarkable clarity. He conceived of the spectrum of an element as composed of the superposition of three different types of series - one in which the lines were comparatively sharp, one in which the lines were more diffuse, and a third that he called principal series even though they consisted mostly of lines in the ultraviolet. The first lines were located in the visible spectrum and were usually the most intense. The members of each series might be single, double, triple, or of higher multiplicity. Any particular elementary spectrum might contain any number (even zero) of series of each of the basic types.""(DSB).‎