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Fine structure constant

It is also renowned as the Sommerfeld constant. So, its name signifies that it is a constant quantity introduced by the German physicist Arnold Sommerfeld in 1916 to determine the size of fine-structure splitting of the hydrogen spectrum.<br>fine structure constant.<br><br>For more information on this topic, kindly visit our blog post at;<br> https://jayamchemistrylearners.blogspot.com/2022/04/bohr-sommerfeld-model-chemistrylearners.html

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Fine structure constant

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  1. Fine structure constant α = 1/137 By Jayam chemistry learners

  2. Introduction: It is also renowned as the Sommerfeld constant. So, its name signifies that it is a constant quantity introduced by the German physicist Arnold Sommerfeld in 1916 to determine the size of fine-structure splitting of the hydrogen spectrum. In fact, Sommerfeld extended the Bohr atomic model to explain the fine structures of the hydrogen spectrum by introducing the relativistic variation of electron mass with velocity in the elliptical electron orbits.

  3. To account for the amount of splitting of spectral lines, he entailed a term that he named fine structure constant. In Sommerfeld's analysis, it was the ratio of the electron's velocity in the ground state of the relativistic Bohr atom to the speed of the light in the vacuum. And he used the Greek letter α (alpha) to symbolize it.

  4. Overview With its help, Sommerfeld could accurately express the gap in the energy difference between the coarse and fine structures of the spectral lines in the hydrogen atom. Hence, it should quantify the electromagnetic interaction of the electrically charged elementary particles and the photon (light radiation).

  5. • For that, he conceptualized α as a quantity with no physical dimension having the SI unit of measurement of 1, which we call dimensionless quantity. • Hence, α is purely a number with a value equal to 1/137, independent of the system of units. Moreover, this fundamental physical constant appeared naturally in Sommerfeld's fine • lines analysis, which agreed well with the experimental observations. • But, it became noteworthy after Paul Dirac gave the exact fine structure formula with his linear relativistic wave equation in 1928.

  6. Measurement: The preferred α measurements methods are; 1. Quantum Hall effect or measurement of electron anomalous magnetic moments 2. Photon recoil in atom interferometry The quantum electrodynamics theory predicts the relationship between the electron magnetic moment (also referred to as the Lande g-factor) and the fine structure constant. The most precise value of α was obtained experimentally on measurement of Lande g- factor by using quantum cyclotron apparatus that involved Feynman diagrams.

  7. Is fine structure constant really a constant quantity? Many physicists thought that α is not constant with the change of space or time. Measurements of hydrogen and deuterium spectral lines showed that the fine structure constant varies negligibly by altering time or location in the Universe. But, beyond their expectations, it was found that the fine structure constant is a function of energy. The quantum electrodynamics shows the logarithmic growth of electromagnetic interaction with the relevant energy scale. Additionally, the electron-positron annihilation proceeds with the production of photons at low energies.

  8. It affects the strength of the electrostatic force. Hence, the value of α is approximately equal to 1/137 for lightest charged particles (like electrons and positrons) at low energies. Conversely, at higher energies, there are particle and anti-particle contributions in addition to electron-positron pairs, which increases the value of α. Hence, for heavier particles like W, Z, Higgs Boson, and a top quark, the value of α is 1/128. Hence, with the development of quantum electrodynamics, the fine structure constant exposure has grown from spectroscopic explanations to coupling constant for the electromagnetic field.

  9. For more information on this topic, kindly visit our blog article at; https://jayamchemistrylearners.blogspot.com/2022/04/bohr-sommerfeld-model- chemistrylearners.html Our blog discusses interesting topics of chemistry with regular new post updates. You can have a look at it and follow it. https://jayamchemistrylearners.blogspot.com/ You can send your valuable suggestions and any doubts regarding chemistry subject through these social media channels. Instagram : https://www.instagram.com/chemistrylearners/ Pinterest : https://in.pinterest.com/kameswariservices/_created/ Facebook https://www.facebook.com/jayamchemistrylearners

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