Posterates of Bora

Niels Bohr is a famous Danish scientist who first proved the incompatibility of the classical laws of physics and atoms. In connection with this, he introduced two assumptions, known nowadays, as Bohr's quantum postulates. They rely on the model of the atom, once proposed by E. Rutherford, according to which he (the atom) has a structure similar to the structure of the universe: the electrons of the atom are in continuous motion around a fixed particle - the nucleus. At first such a model was considered ideal and completely describing and explaining all the experiments connected with the atom. However, later it became clear that this model is not able to answer the question about the existence of an atom and its stability.

According to the planetary model, the motion of electrons around a stationary nucleus must necessarily be accompanied by the emission of electromagnetic waves, whose frequency equals the rotation frequency of negatively charged elements around the center. As a result, the electron energy must constantly decrease, which, in turn, leads to its greater attraction to the nucleus. However, experiments show that this does not happen. An atom in general is a stable system that can exist for a long period without impact of influence from outside. The radiation of an atom can be called discrete; Intermittent, which, naturally, indicates the fact of periodicity of the study, and not its constancy. In other words, scientists came to the conclusion that the application of classical physics laws to explain the existence of electrons is impossible.

Only in 1913, introduced by Bohr assumptions allowed to explain the example of the hydrogen atom principles of energy emission by electrons.

The conclusions made by Bohr were empirically confirmed by many scientists of that time. On the basis of his assumptions, an entire theory was created, which later became a special case of quantum mechanics. The postulates of Bohr look like this:

1. The atomic system emits energy, conditionally called En, only in quantum states. Otherwise (when the atom is in a stationary state), energy is not released.

In this case, the stationary state is understood to mean the motion of electrons along certain orbits. Despite the actual presence of accelerated motion, electromagnetic waves are not emitted, the atom has only a quantum energy value.

2. The second postulate, most commonly known as a frequency rule, indicates that the transition of an atom from one state to another (usually from a stationary state to a quantum state) is accompanied by the release or absorption of energy. This process is carried out in small portions - quanta. Their value corresponds to the difference in the energy of the states between which the transition actually takes place. The second postulate allows us to calculate from the known experimental values of the energies of stationary states of the radiation frequency of a hydrogen atom.

The postulates of Bohr are applicable to explaining the absorption and emission of light by a hydrogen particle. Actually, this is exactly how Bor himself once confirmed his conclusions. The postulates of Bohr allowed modern scientists to construct a theory of the hydrogen spectrum. It is noteworthy that the construction of a quantitative theory of the spectrum of the next element, helium, turned out to be practically impracticable.

Nevertheless, the postulates of Bohr - a physicist who laid a strong brick in the foundation of quantum theory, to this day are the most important observations and conclusions. In particular, it was possible to construct a theory of absorption and emission of light, which can not be done on the basis of data from classical physics alone.

Bohr's postulates allowed him to breathe new life into classical mechanics. To this day they remain indisputable within the framework of quantum mechanics.