This classic work by the Nobel Laureate elaborates on the correspondence principle, discussing the theory's applications from a uniform point of view and considering the underlying assumptions in their relations to ordinary mechanics and electrodynamics. Bohr closely traces the analogy between quantum theory and ordinary theory of radiation. 1918-1922 editions.

Explains the phenomena that classical physics could not explain but quantum physics could, the photoelectric effect and line spectra.

For beginners and specialists in other fields: the Nobel Laureate's introduction to atomic spectra and their relationship to atomic structures, stressing basics in a physical, rather than mathematical, treatment. 80 illustrations.

Bohr and Planck helped shaped the cultural landscape of the world today. Now their work is available here in a digestible, pocket format for the modern reader. A concise, uncluttered edition for the modern reader, with a new introduction. Quantum Theory contains two foundational works of quantum research from the early years of the 20th Century, representing breakthroughs in science that radically altered the landscape of modern knowledge: Quantum Theory of Line-Spectra by Niels Bohr and The Origin and Development of the Quantum Theory by Max Planck. The FLAME TREE Foundations series features core publications which together have shaped the cultural landscape of the modern world, with cutting-edge research distilled into pocket guides designed to be both accessible and informative.

The standard comprehensive work on the theory of atomic spectra. "...a work of the first rank...." Nature

Group Theory and its Application to the Quantum Mechanics of Atomic Spectra describes the applications of group theoretical methods to problems of quantum mechanics with particular reference to atomic spectra. The manuscript first takes a look at vectors and matrices, generalizations, and principal axis transformation. Topics include principal axis transformation for unitary and Hermitian matrices; unitary matrices and the scalar product; linear independence of vectors; and real orthogonal and symmetric matrices. The publication also ponders on the elements of quantum mechanics, perturbation theory, and transformation theory and the bases for the statistical interpretation of quantum mechanics. The book discusses abstract group theory and invariant subgroups, including theorems of finite groups, factor group, and isomorphism and homomorphism. The text also reviews the algebra of representation theory, rotation groups, three-dimensional pure rotation group, and characteristics of atomic spectra. Discussions focus on eigenvalues and quantum numbers, spherical harmonics, and representations of the unitary group. The manuscript is a valuable reference for readers interested in the applications of group theoretical methods.