# How did Bohr come up with his model before De Broglie?

1. Aug 16, 2012

### Lamarr

Doesn't the Bohr model use standing waves as a reference? Before De Broglie's hypothesis, how did Bohr manage to assume that electrons are waves?

2. Aug 16, 2012

### Staff: Mentor

No.

He didn't. His original model of 1915 or thereabouts did not use waves at all in describing the hydrogen atom's electrons, as far as I know.

Bohr "explained" hydrogen's discrete energy levels by assuming that the electron's orbital angular momentum is quantized: $L = mvr = n \hbar$. This of course begs the question, "why is L quantized?" The Bohr-Sommerfeld model generalized the quantization of L to the quantization of the "action integral", which allows for both circular and elliptical orbits. But this line of thought soon petered out because of inconsistency with various experiments. See the Wikipedia article on the Bohr model for a bit about this. For more, see for example the textbook by Eisberg & Resnick.

Last edited: Aug 16, 2012
3. Aug 16, 2012

### Lamarr

ah makes perfect sense, and fits in very nicely with de broglie's equation, which is based on planck's eqn and relativistic momentum.

Now i see how QM and Relativity come together. Thanks.