Back نظرية الكم القديمة Arabic Antiga teoria quàntica Catalan Quantenphysik#Frühe Quantentheorien German Teoría cuántica antigua Spanish نظریه کوانتومی قدیمی Persian Théorie des quanta French Teori kuantum lama ID Teoria dei quanti Italian 前期量子論 Japanese 초기 양자론 Korean
The old quantum theory is a collection of results from the years 1900–1925 which predate modern quantum mechanics. The theory was never complete or self-consistent, but was instead a set of heuristic corrections to classical mechanics. The theory has come to be understood as the semi-classical approximation to modern quantum mechanics. The main and final accomplishments of the old quantum theory were the determination of the modern form of the periodic table by Edmund Stoner and the Pauli exclusion principle, both of which were premised on Arnold Sommerfeld's enhancements to the Bohr model of the atom. The main tool of the old quantum theory was the Bohr–Sommerfeld quantization condition, a procedure for selection of certain allowed states of a classical system: the system can then only exist in one of the allowed states and not in any other state.