|
The Bohr-Kramers-Slater (BKS) theory〔N. Bohr, Collected Works, J. Kalckar, ed. North-Holland, Amsterdam, etc., 1985, Vol. 5, pp. 3-216.〕〔J. Mehra and H. Rechenberg, The historical development of quantum theory, Springer-Verlag, New York, etc., 1982, Vol. 1, Part 2, pp. 532-554.〕〔N. Bohr, H.A. Kramers, and J.C. Slater, Phil. Mag. 47, 785-802 (1924) (German version: Zeitschr. f. Physik 24, 69-87 (1924)).〕 was perhaps the final attempt at understanding the interaction of matter and electromagnetic radiation on the basis of the so-called Old quantum theory, in which quantum phenomena are treated by imposing quantum restrictions on classically describable behaviour. It was advanced in 1924, and sticks to a ''classical'' wave description of the electromagnetic field. It was perhaps more a research program than a full physical theory, the ideas that are developed not being worked out in a quantitative way. One aspect, the idea of modelling atomic behaviour under incident electromagnetic radiation using "virtual oscillators" at the absorption and emission frequencies, rather than the (different) apparent frequencies of the Bohr orbits, significantly led Born, Heisenberg and Kramers to explore mathematics that strongly inspired the subsequent development of matrix mechanics, the first form of modern quantum mechanics. The provocativeness of the theory also generated great discussion and renewed attention to the difficulties in the foundations of the old quantum theory.〔Max Jammer, ''Conceptual Development of Quantum Mechanics'', 2e, 1989, p.188〕 However, physically the most provocative element of the theory, that momentum and energy would not necessarily be conserved in each interaction but only overall, statistically, was soon shown to be in conflict with experiment. == Origins == The initial idea of the BKS theory originated with Slater,〔Letters from J.C. Slater, November, December 1923, reprinted in Ref. 1, pp. 8, 9.〕 who proposed to Bohr and Kramers the following elements of a theory of emission and absorption of radiation by atoms, to be developed during his stay in Copenhagen: # Emission and absorption of electromagnetic radiation by matter is realized in agreement with Einstein's photon concept; # A photon emitted by an atom is guided by a classical electromagnetic field (compare de Broglie's ideas published September 1923 〔L. de Broglie, Comptes Rendues 177, 507-510 (1923).〕) consisting of spherical waves, thus enabling to explain interference; # Even when there are no transitions there exists a classical field to which all atoms contribute; this field contains all frequencies at which an atom can emit or absorb a photon, the probability of such an emission being determined by the amplitude of the corresponding Fourier component of the field; the probabilistic aspect is provisional, to be eliminated when the dynamics of the inside of atoms are better known; # The classical field is not produced by the actual motions of the electrons but by `motions with the frequencies of possible emission and absorption lines' (to be called `''virtual'' oscillators', creating a field to be referred to as `virtual' as well). 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「BKS theory」の詳細全文を読む スポンサード リンク
|