Hydrogen-atom electrons can be in 1s orbital or 1p orbital. Hydrogen-atom 1s-to-1p electronic transition has the smallest electronic-transition energy, equivalent to microwave photons. Microwaves have lower frequencies than optical waves and so have smaller Doppler broadening. This system is optimum to measure the fine-structure constant. Microwaves excite hydrogen-atom same-spin electrons from 1s to 1p orbitals {Lamb shift, electron} [1947] (Willis E. Lamb, Jr., and Robert Retherford) (Hans Bethe) to measure the fine-structure constant, which indicates virtual photons.
Physical Sciences>Physics>Matter>Atom>Wavelength Change>Doppler
5-Physics-Matter-Atom-Wavelength Change-Doppler
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Date Modified: 2022.0224