I Explanation of the Bohr postulates' existence

[Timothy S.]

TL;DR Summary

Are there any explainations why Bohr postulates take place?

I know that the word 'postulate' means something without explanation, so probably there are no words like 'electrons have stable orbits and radiate only when transiting from one to another, because .....' in quantum mechanics books, but were there at least worthy of mentioning attempts to explain why Bohr postulates take place?

 

[PeroK]

TL;DR Summary: Are there any explainations why Bohr postulates take place?

I know that the word 'postulate' means something without explanation, so probably there are no words like 'electrons have stable orbits and radiate only when transiting from one to another, because .....' in quantum mechanics books, but were there at least worthy of mentioning attempts to explain why Bohr postulates take place?

Bohr's model of the atom was an ad hoc intermediate step towards quantum mechanics. It was based more on guesswork than formal postulates. That said, QM itself can be built up from some formal postulates. For example:

https://www.sydney.edu.au/science/chemistry/~mjtj/CHEM3117/Resources/postulates.pdf

 

[Albertus Magnus]

It took some time before quantum mechanics was fleshed out in the mature form we have it today; there is a pretty good span of time between Plank's quantum hypothesis and the publication of Von Neumann's classic work on the foundations of quantum mechanics.

Bohr's treatment of the hydrogen atom is the third major attempt at using quantum reasoning to solve an otherwise intractable problem in physics (Einstein's use of the hypothesis to treat photoelectric phenomena was the second).

To tackle the problem of elucidating the spectra of the hydrogen atom, Bohr used the then revolutionary quantum hypothesis applied to the orbital angular momentum of the hydrogen atom's electron along with the correspondence principle to extend classical methods in Hamilton-Jacobi formalism to "quantize" the motion of the atomic electron thereby ushering the atom into the quantum age.

Thus, the primary reason behind Bohr's quantum assumption is that the empirical observations of experimental physics demanded something to account for the failure classical theoretical physics to explain the behavior of the simplest atomic systems. It was a radical out of the box approach that happened to work.

 

[jtbell]

Bohr was trying to explain the emission spectra of hydrogen (with its single electron) and single-electron ions such as He⁺ and Li⁺⁺. Balmer and Rydberg had noticed that those wavelengths could be summarized by simple formulas. Bohr found that he could derive those formulas by making certain assumptions about atomic structure, using discrete classical planetary-style orbits for the electrons in the electric field of the nucleus.