Bohr theory, a theory about atomic structure. 19 13 was put forward by Bohr. It is based on Rutherford's atomic model and Planck's quantum concept. The main points are:

(1) Electrons outside the nucleus can only run in certain specified orbits, and do not emit light at this time;

(2) When electrons jump from high-energy orbit to low-energy orbit, atoms emit light.

Specifically, Bohr's theory includes three hypotheses.

1. Quantum Hypothesis of Atomic Energy: Atoms can only be in a series of discontinuous energy states, in which they are stable. Although electrons will accelerate, they will not radiate energy.

2. Atomic energy level transition hypothesis: when an atom transitions from one steady state to another, it radiates photons with a certain frequency, and the energy of photons is determined by the energy difference between the two steady States.

3. Quantization hypothesis of electron motion orbit in atoms: different energy states of atoms correspond to different electron motion orbits. Because the energy state of the atom is discontinuous, the orbit of the electron may also be discontinuous, that is, the electron cannot move in an orbit with any radius.

Danish physicist Bohr first applied the quantum hypothesis to atoms and explained the discontinuity of atomic spectrum. He believes that electrons only move around the nucleus in a certain circular orbit. When running in these orbits, it does not emit energy, but only emits radiation when it transitions from a higher energy orbit to a lower orbit, otherwise it absorbs radiation. This theory not only solves the problem of atomic stability on the basis of Rutherford model, but also completely accords with the experimental results obtained by spectral analysis when applied to hydrogen atoms, thus causing a shock in physics. Bohr instructed physicists in 19 to understand the basic structure of quantum theory from1920s to1920s, which sounds contradictory. In fact, he is both a midwife and a nurse of this theory. Bohr's quantized atomic structure obviously violates the classical theory, and also attracts many scientists' dissatisfaction. However, its unexpected success in explaining the empirical law of spectral distribution has earned it a high reputation. But Bohr's theory can only be used to solve the simple case of hydrogen atom, which can't be explained for multi-electron atom spectrum. The old quantum theory faced a crisis, but it was soon broken through. The first breakthrough in this respect was made by French physicist De Broglie. He majored in history at university, but his brother is a famous physicist who studies X-rays. Influenced by him, after graduating from De Broglie University, he turned to study physics and studied X-ray fluctuations and particles with his brother. After a long time of thinking, de Broglie suddenly realized that Einstein's theory of light quantum should be extended to all matter particles, especially electrons. From September 1923 to September 10, he published three papers in succession, put forward the theory that electrons are also a kind of wave, and introduced the concept of "standing wave" to describe the radiation-free static state of electrons in atoms. Standing waves are contrary to traveling waves moving on lakes or lines, and the vibration on guitar strings is standing waves. In this way, the position of electrons can be described in the form of wave function. But what it gives is not the familiar certainty, but the statistical "distribution probability", which well reflects the distribution and operation of electrons in space. De Broglie also predicted that the electron beam will also diffract when it passes through the small hole. 1924, he wrote his doctoral thesis "research on quantum theory", which systematically expounded the theory of matter wave, and Einstein appreciated it very much. Within a few years, experimental physicists really observed the diffraction phenomenon of electrons, which confirmed the existence of de Broglie matter wave.