On the Quantum Theory of Radiation and the Structure of the Atom. (+) On the Decrease of velocity of Swiftly Moving Electrified Particles passing through Matter. (2 papers).

London, Taylor & Francis, 1915. Contemp. hcalf. Spine gilt, title- and tomelabels with gilt lettering. Spine a bit rubbed, some cracking to hinges, but covers not detached. In: "The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science", Vol. XXX, Sixth Series. VIII,824 pp., textillustr. and 18 plates. (Entire volume offered). Bohr's papers: pp. 394-413 and pp. 581-612. A stamp to verso of titlepage. Internally clean and fine. First appearance of a landmark paper in which Bohr found experimental support for his energy equation for electron orbits and of stationary states in the work of Franck and Hertz from 1914. Furthermore, Franck and Hertz unwittingly provided an independent confirmation of the concept of stationary state. In 1914 they observed an energy threshold in the electron-stopping power of mercury vapor. This threshold, Bohr explained the following year, corresponded to a transition between the normal state and another (first excited) stationary state of the mercury atom (and not, as Franck and Hertz had originally thought, to the ionization of the atom). The supramechanical stability implied by the assumption of stationary states was now empirically proved to comprehend stability with regard to electron impacts."Bohr had to frequently revise and refine his atomic model in light of new discoveries. One significant paper "On the Quantum Theory of Radiation and the Structure of the Atom," (the paper offered) added more specific details about atomic states. For example Bohr had earlier made the argument that electrons could jump from one orbit to another as energy was emitted or absorbed. In this paper, he theorezed that an atom possesses stationary states in which energy was neither emitted nor absorbed. Any emission or absorption that did occur, such as might induce an electron ump, would correspond to the transition between two stationary states."(sparknotes.com).An: the second paper offered. When Bohr had finished his importent paper on the hydrogen atom "On the Theory of Decrease of Velocity of Moving Electrified Particles on passing through Matter" 1913, he completed another paper on that subject (the paper offered), which includes the influence of effects due to relativity and to straggling (that is, the fluctuations in energy and in range of individual particles).(Pais p. 128).Rosenfeld no 13 a. 14.The volume contains further importent papers by J.J. THOMSON, W.H. BRAGG, RUTHERFORD & BARNES, SODDY & HITCHINS etc.…