<Dd> n λ = 2 π r . (\ displaystyle n \ lambda = 2 \ pi r ~ .) </Dd> <P> Bohr described angular momentum of the electron orbit as 1 / 2h while de Broglie's wavelength of λ = h / p described h divided by the electron momentum . In 1913, however, Bohr justified his rule by appealing to the correspondence principle, without providing any sort of wave interpretation . In 1913, the wave behavior of matter particles such as the electron (i.e., matter waves) was not suspected . </P> <P> In 1925, a new kind of mechanics was proposed, quantum mechanics, in which Bohr's model of electrons traveling in quantized orbits was extended into a more accurate model of electron motion . The new theory was proposed by Werner Heisenberg . Another form of the same theory, wave mechanics, was discovered by the Austrian physicist Erwin Schrödinger independently, and by different reasoning . Schrödinger employed de Broglie's matter waves, but sought wave solutions of a three - dimensional wave equation describing electrons that were constrained to move about the nucleus of a hydrogen - like atom, by being trapped by the potential of the positive nuclear charge . </P> <P> The Bohr model gives almost exact results only for a system where two charged points orbit each other at speeds much less than that of light . This not only involves one - electron systems such as the hydrogen atom, singly ionized helium, and doubly ionized lithium, but it includes positronium and Rydberg states of any atom where one electron is far away from everything else . It can be used for K - line X-ray transition calculations if other assumptions are added (see Moseley's law below). In high energy physics, it can be used to calculate the masses of heavy quark mesons . </P>

Who discovered the quantum mechanical model of the atom