Electron cloud densitometry

Electron cloud densitometry is an interdisciplinary technology that uses the principles of quantum mechanics by the electron beam shifting effect. The effect is that the electron beam passing through the electron cloud, in accordance with the general principle of superposition of the system, changes its intensity in proportion to the probability density of the electron cloud. It gives direct visualization of the individual shapes of atoms, molecules and chemical bonds.It is a purely quantum mechanical phenomenon that does not exist in elementary physics.
History
Philosophical atomism
The idea that matter is made up of discrete units is a very old. Democritus (460-370 BC) called these units atoms. He taught that atoms were infinite in number, uncreated, and eternal, and that the qualities of an object result from the kind of atoms that compose it.
Quantum physical models of atoms
In 1924, Louis de Broglie proposed that all moving particles—particularly subatomic particles such as electrons—exhibit a degree of wave-like behavior. Erwin Schrödinger, fascinated by this idea, explored whether or not the movement of an electron in an atom could be better explained as a wave rather than as a particle. Schrödinger's equation, published in 1926, describes an electron as a wave function instead of as a point particle. This approach elegantly predicted many of the spectral phenomena that Bohr's model failed to explain.
One of its critics, Max Born, proposed instead that Schrödinger's wave function did not describe the physical extent of an electron (like a charge distribution in classical electromagnetism), but rather gave the probability that an electron would, when measured, be found at a particular point. This reconciled the ideas of wave-like and particle-like electrons: the behavior of an electron, or of any other subatomic entity, has both wave-like and particle-like aspects. The precise mathematical statement of the position-momentum uncertainty principle is due to Earle Hesse Kennard, Wolfgang Pauli, and Hermann Weyl.) This invalidated Bohr's model, with its neat, clearly defined circular orbits. The modern model of the atom describes the positions of electrons in an atom in terms of probabilities. An electron can potentially be found at any distance from the nucleus, but, depending on its energy level and angular momentum, exists more frequently in certain regions around the nucleus than others; this pattern is referred to as its atomic orbital. The shapes of atomic orbitals are found by solving the Schrödinger equation; however, analytic solutions of the Schrödinger equation are known for very few relatively simple model Hamiltonians including the hydrogen atom. Even the helium atom—which contains just two electrons—has defied all attempts at a fully analytic treatment.
Attempts to visualize the shapes of atoms
The plum pudding model is first model of an atom shape. This model is proposed by J. J. Thomson in 1904., soon after the discovery of the electron.
In 1911, Ernest Rutherford, an experiment with scattering alpha particles showed that a positively charged substance is concentrated in the nucleus, which is at least 3,000 times smaller than the size of an atom.
Erwin Schrödinger, Werner Heisenberg and others led to the full development of quantum mechanics in the mid-1920s, which showed the rotational motion of light electrons around a heavy nucleus. Electrons fill the entire volume of the atom. In this regard, Richard Feynmanproposed to consider an atom in the form of a cloud, whose electron cloud density is proportional to the probability density for observing the electron. Thus “picture” of an atom is a nucleus surrounded by an “electron cloud”.
Electron cloud density of atoms, molecules and chemical bonds
In its efforts to learn as much as possible about nature, modern physics has found that electron clouds can be “known” with certainty. Direct visualization of individual electron cloud was obtained in 2018 Olexandr P. Kucherov a physicist from Ukraine. that was later named after him. It is active due to polarization and weaker than covalent and ionic bonds. This force plays a major role in allotropes of carbon. So in the Encyclopedia Britannica under the watchword we can read about graphite "The interlayer distance (337 pm) is sufficiently large to preclude localized bonding between the layers; the bonding between layers is probably by van der Waals interaction". The prominent quantum chemist Charles Coulson in his book from 1961 entitled Valence wrote on page 391: "The distance between successive planes is 335 pm, a value so large that it can only arise from van der Waals forces". The van der Waals force is present in monolayer graphene and in activated carbon.
The direct visualization of the van der Waals forces in activated carbon, graphite, graphene and diamond (allotropes of carbon) is shown in a number of electron cloud densitometry images. Subsequently, by electron cloud densitometry, this substance was synthesized in an amount sufficient for laboratory studies<ref name=Rud2 />

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