Exclusion Principle of Wolfgang Ernst Pauli | Quantum Science Philippines
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Exclusion Principle of Wolfgang Ernst Pauli

Rommel J. Jagus

Wolfgang Ernst Pauli was one of the great contributors of quantum mechanics. He was an Austrian-born Swiss physicist and a Nobel laureate. He was born in Vienna Austria – Hungary on April 25 of year 1900. In 1918, he finished his early education in Vienna. He received his Ph.D. in July 1921 for his thesis on the quantum theory of ionized molecular hydrogen under his doctoral adviser Arnold Sommerfeld.

Pauli was influenced by Bohr’s lectures in understanding the concept of atomic model. The question, as to why all electrons for an atom in the ground state were not bound in the innermost shell, that Bohr tried to answer has no convincing explanations during his lectures in Gottingen. Pauli’s eager to answer the question also led to answer another phenomenon. He was in Copenhagen when he made a serious effort to explain the formation of douplet-spectra of the alkali metals spectra for which they called the Anomalous Zeeman Effect. This type of splitting exhibited of the spectral lines in a magnetic field is different from the normal triplet by normal Zeeman Effect. The reason of Bohr was that a non-vanishing angular momentum of the atomic core was supposed cause of this douplet structure. Pauli argues with this reason which he rejected and instead of it he proposed a new quantum theoretic property of the electron, which he called a “two-valuedness not describable classically”. The idea of electron spin were introduced by Uhlenbeck and Goudsmit, which made Pauli understand the anomalous Zeeman effect by simply assuming a spin quantum number of one electron is equal 1/2. Since then, idea of exclusion principle has been closely connected with the idea of spin. The idea of spin is then become essential to quantum-mechanical property of electron and to the field of quantum mechanics. Hence, exclusion principle states that no two electrons can occupy the same quantum or energy state of an atom simultaneously.

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