= Timeline of quantum mechanics
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* 1859-1900: see <black-body radiation experiments>{full}. Continuously improving culminating in <Planck's law> <black-body radiation> and <Planck's law>
* 1905 <photoelectric effect> and the <photon>
* TODO experiments
* 1905 Einstein's photoelectric effect paper. Planck was intially thinking that light was continuous, but the atoms vibrated in a discrete way. Einstein's explanation of the photoelectric effect throws that out of the window, and considers the photon discrete.
* 1913 <atomic spectra> and the <Bohr model>
* 1885 <Balmer series>, an <empirical formula> describes some of the lines of the <hydrogen emission spectrum>
* 1888 <Rydberg formula> generalizes the <Balmer series>
* 1896 <Pickering series> makes it look like a star has some new kind of hydrogen that produces half-integer entries in the <Pickering series>
* 1911 Bohr visits <J. J. Thomson> in the <University of Cambridge> for his postdoc, but they don't get along well
* Bohr visits <Rutherford> at the <University of Manchester> and decides to transfer there. During this stay he becomes interested in problems of the electronic structure of the atom.
Bohr was forced into a quantization postulate because spinning electrons must radiate energy and collapse, so he postulated that electrons must somehow magically stay in orbits without classically spinning.
* 1913 february: young physics professor Hans Hansen tells Bohr about the <Balmer series>. This is one of the final elements Bohr needed.
* 1913 <Bohr model> published predicts atomic spectral lines in terms of the <Planck constant> and other <physical constant>.
* explains the <Pickering series> as belonging to inoized <helium> that has a single <electron>. The half term in the spectral lines of this species come from the nucleus having twice the charge of hydrogen.
* 1913 March: during review before publication, Rutherford points out that <causality and quantum jumps are incompatible>[instantaneous quantum jumps don't seem to play well with causality].
* 1916 <Bohr-Sommerfeld model> introduces <angular momentum> to explain why some lines are not observed, as they would violate the conservation of angular momentum.