Pauli's Exclusion Principle: The origins of the exclusion principle: an extremely natural prescriptive rule

摘要: The exclusion principle was the final outcome of Pauli's struggle to understand some spectroscopic anomalies in early 1920s: doublets were observed spectra alkali metals, singlets and triplets alkaline earths, even more anomalous patterns when chemical elements placed an external magnetic field (anomalous Zeeman effect Paschen–Back effect). These challenged old quantum theory, prompted a radical theoretical change (Section 2.1). From 1920 1924 Alfred Lande, Werner Heisenberg, Niels Bohr all engaged trying save traditional model (the so-called atomic core model) reconcile it with anomalies. impasse solved only introduction fourth degree freedom for electron, consequent demise 2.2). What Pauli called ‘twofoldness’ [ Zweideutigkeit ] electron's angular momentum soon reinterpreted as spin 2.3). rule announced this semi-classical context that characterized revolutionary transition from theory new around 1925. prehistory Atomic Bohr–Sommerfeld structure existence spectral lines had been known scientists since beginning nineteenth century Wollaston Fraunhofer first dark absorption spectrum Sun.