In this photo you are looking at the first direct image of the orbits of an electron around an atom - in fact, the wave function of an atom!
To capture a photograph of the orbital structure of a hydrogen atom, the researchers used the latest quantum microscope, an incredible device that allows scientists to peer into the realm of quantum physics.
The orbital structure of space in an atom is occupied by an electron. But in describing these microscopic properties of matter, scientists rely on wave functions, mathematical ways of describing the quantum states of particles, namely how they behave in space and time.
As a rule, formulas like the Schrödinger equation are used in quantum physics to describe the states of particles.
Obstacles in the path of researchers
Until now, scientists have never actually observed the wave function. Trying to capture the exact position or momentum of a lone electron was like trying to catch a swarm of flies. Direct observations were distorted by a very unpleasant phenomenon - quantum coherence.
To measure all quantum states, you need an instrument that can take many measurements of the states of a particle over time.
But how to increase the already microscopic state of a quantum particle? The answer was found by a group of international researchers. With a quantum microscope, a device that uses photoionization to directly observe atomic structures.
In her article in the popular journal Physical Review Letters, Aneta Stodolna at the Institute of Molecular Physics (AMOLF) in the Netherlands describes how she and her team obtained the nodal electron orbital structures of a hydrogen atom placed in a static electric field.
Method of work
After irradiation with laser pulses, ionized electrons left their orbits and along the measured trajectory fell into a 2D detector (double microchannel plate. The detector is located perpendicular to the field itself). There are many trajectories along which electrons can travel before colliding with the detector. This provides researchers with a set of interference patterns, models that reflect the nodal structure of the wave function.
The researchers used an electrostatic lens that magnifies the outgoing wave of electrons by more than 20,000 times.
Physicists from the United States managed to capture individual atoms in a photo with a record resolution, Day.Az reports with reference to Vesti.ru
Scientists from Cornell University in the United States managed to capture individual atoms in a photo with a record resolution of less than half an angstrom (0.39 Å). Previous photographs had half the resolution - 0.98 Å.
Powerful electron microscopes that can see atoms have been around for half a century, but their resolution is limited by the long wavelength of visible light, which is larger than the diameter of an average atom.
Therefore, scientists use a kind of analogue of lenses that focus and magnify the image in electron microscopes - they are a magnetic field. However, fluctuations in the magnetic field distort the result. To remove distortions, additional devices are used that correct the magnetic field, but at the same time increase the complexity of the electron microscope design.
Previously, physicists at Cornell University developed the Electron Microscope Pixel Array Detector (EMPAD), which replaces a complex system of generators that focus incoming electrons with a single small 128x128 pixel array that is sensitive to individual electrons. Each pixel registers the angle of electron reflection; Knowing it, scientists using the technique of ptyicography reconstruct the characteristics of the electrons, including the coordinates of the point from which it was released.
Atoms in the highest resolution
David A. Muller et al. Nature, 2018.
In the summer of 2018, physicists decided to improve the quality of the resulting images to a record-breaking resolution to date. Scientists fixed a sheet of 2D material - molybdenum sulfide MoS2 - on a movable beam, and released electron beams by turning the beam at different angles to the electron source. Using EMPAD and ptyicography, scientists determined the distances between individual molybdenum atoms and obtained an image with a record resolution of 0.39 Å.
"In fact, we have created the smallest ruler in the world," explains Sol Gruner (Sol Gruner), one of the authors of the experiment. In the resulting image, it was possible to see sulfur atoms with a record resolution of 0.39 Å. Moreover, we even managed to see the place where one such atom is missing (indicated by an arrow).
Sulfur atoms at record resolution
Let's try. I don’t think that everything written below is completely true, and I could well have missed something, but the analysis of existing answers to similar questions and my own thoughts lined up like this:
Take a hydrogen atom: one proton and one electron in its orbit.
The radius of a hydrogen atom is just the radius of the orbit of its electron. In nature, it is equal to 53 picometers, that is, 53 × 10^-12 meters, but we want to increase it to 30 × 10^-2 meters - about 5 billion times.
The diameter of a proton (that is, our atomic nucleus) is 1.75×10^−15 m. If you increase it to the desired size, it will be 1×10^−5 meters in size, that is, one hundredth of a millimeter. It is indistinguishable to the naked eye.
Let's better increase the proton immediately to the size of a pea. The orbit of the electron will then be the radius of a football field.
The proton will be a region of positive charge. It consists of three quarks, which are about a thousand times smaller than it - we will definitely not see them. There is an opinion that if this hypothetical object is sprinkled with magnetic chips, it will gather around the center into a spherical cloud.
The electron will not be visible. No ball will fly around the atomic nucleus, the "orbit" of the electron is just a region, at different points of which the electron can be located with different probabilities. You can imagine this as a sphere with a diameter of a stadium around our pea. At random points inside this sphere, a negative electric charge appears and instantly disappears. Moreover, it does it so quickly that even at any single moment of time it makes no sense to talk about its specific location ... yes, it's incomprehensible. Simply put, it doesn't "look" at all.
It is interesting, by the way, that by increasing the atom to macroscopic dimensions, we hope to "see" it - that is, to detect the light reflected from it. In fact, ordinary-sized atoms do not reflect light; on an atomic scale, we are talking about interactions between electrons and photons. An electron can absorb a photon and move to the next energy level, it can emit a photon, and so on. With this system hypothetically enlarged to the size of a football field, too many assumptions would be needed to predict the behavior of this impossible structure: would a photon have the same effect on a giant atom? Is it necessary to "look" at it by bombarding it with special giant photons? Will it emit giant photons? All these questions are, strictly speaking, meaningless. I think, however, it is safe to say that the atom will not reflect light in the way that a metal ball would.
As you know, everything material in the Universe consists of atoms. An atom is the smallest unit of matter that carries its properties. In turn, the structure of an atom is made up of a magical trinity of microparticles: protons, neutrons and electrons.
Moreover, each of the microparticles is universal. That is, you cannot find two different protons, neutrons or electrons in the world. All of them are absolutely similar to each other. And the properties of the atom will depend only on the quantitative composition of these microparticles in the general structure of the atom.
For example, the structure of a hydrogen atom consists of one proton and one electron. Next in complexity, the helium atom is made up of two protons, two neutrons, and two electrons. A lithium atom is made up of three protons, four neutrons and three electrons, etc.
Structure of atoms (from left to right): hydrogen, helium, lithium
Atoms combine into molecules, and molecules combine into substances, minerals and organisms. The DNA molecule, which is the basis of all life, is a structure assembled from the same three magical building blocks of the universe as the stone lying on the road. Although this structure is much more complex.
Even more amazing facts are revealed when we try to take a closer look at the proportions and structure of the atomic system. It is known that an atom consists of a nucleus and electrons moving around it along a trajectory that describes a sphere. That is, it cannot even be called a movement in the usual sense of the word. The electron is rather located everywhere and immediately within this sphere, creating an electron cloud around the nucleus and forming an electromagnetic field.
Schematic representations of the structure of the atom
The nucleus of an atom consists of protons and neutrons, and almost the entire mass of the system is concentrated in it. But at the same time, the nucleus itself is so small that if you increase its radius to a scale of 1 cm, then the radius of the entire structure of the atom will reach hundreds of meters. Thus, everything that we perceive as dense matter consists of more than 99% of the energy connections between physical particles alone and less than 1% of the physical forms themselves.
But what are these physical forms? What are they made of, and how material are they? To answer these questions, let's take a closer look at the structures of protons, neutrons, and electrons. So, we descend one more step into the depths of the microcosm - to the level of subatomic particles.
What is an electron made of?
The smallest particle of an atom is an electron. An electron has mass but no volume. In the scientific view, the electron does not consist of anything, but is a structureless point.
An electron cannot be seen under a microscope. It is observed only in the form of an electron cloud, which looks like a fuzzy sphere around the atomic nucleus. At the same time, it is impossible to say with accuracy where the electron is located at a moment in time. Devices are capable of capturing not the particle itself, but only its energy trace. The essence of the electron is not embedded in the concept of matter. It is rather like an empty form that exists only in and through movement.
No structure has yet been found in the electron. It is the same point particle as the quantum of energy. In fact, an electron is energy, however, this is its more stable form than the one represented by photons of light.
At the moment, the electron is considered indivisible. This is understandable, because it is impossible to divide something that has no volume. However, there are already developments in the theory, according to which the composition of an electron contains a trinity of such quasiparticles as:
- Orbiton - contains information about the orbital position of the electron;
- Spinon - responsible for the spin or torque;
- Holon - carries information about the charge of an electron.
However, as we see, quasi-particles have absolutely nothing in common with matter, and carry only information.
Photographs of atoms of different substances in an electron microscope
Interestingly, an electron can absorb energy quanta, such as light or heat. In this case, the atom moves to a new energy level, and the boundaries of the electron cloud expand. It also happens that the energy absorbed by an electron is so great that it can jump out of the atomic system and continue its movement as an independent particle. At the same time, it behaves like a photon of light, that is, it seems to cease to be a particle and begins to exhibit the properties of a wave. This has been proven in an experiment.
Young's experiment
In the course of the experiment, a stream of electrons was directed onto a screen with two slits cut into it. Passing through these slits, the electrons collided with the surface of another projection screen, leaving their mark on it. As a result of this “bombardment” by electrons, an interference pattern appeared on the projection screen, similar to that which would appear if waves, but not particles, passed through two slits.
Such a pattern occurs due to the fact that the wave, passing between the two slots, is divided into two waves. As a result of further movement, the waves overlap each other, and in some areas they cancel each other out. As a result, we get many stripes on the projection screen, instead of one, as it would be if the electron behaved like a particle.
The structure of the nucleus of an atom: protons and neutrons
Protons and neutrons make up the nucleus of an atom. And despite the fact that in the total volume the core occupies less than 1%, it is in this structure that almost the entire mass of the system is concentrated. But at the expense of the structure of protons and neutrons, physicists are divided in opinion, and at the moment there are two theories at once.
- Theory #1 - Standard
The Standard Model says that protons and neutrons are made up of three quarks connected by a cloud of gluons. Quarks are point particles, just like quanta and electrons. And gluons are virtual particles that ensure the interaction of quarks. However, neither quarks nor gluons have been found in nature, so this model is subject to severe criticism.
- Theory #2 - Alternative
But according to the alternative unified field theory developed by Einstein, the proton, like the neutron, like any other particle of the physical world, is an electromagnetic field rotating at the speed of light.
Electromagnetic fields of man and the planet
What are the principles of the structure of the atom?
Everything in the world - subtle and dense, liquid, solid and gaseous - is just the energy states of countless fields that permeate the space of the Universe. The higher the energy level in the field, the thinner and less perceptible it is. The lower the energy level, the more stable and tangible it is. In the structure of the atom, as well as in the structure of any other unit of the Universe, lies the interaction of such fields - different in energy density. It turns out that matter is only an illusion of the mind.
In fact, the author of RFC in his “reflections” went so far that it is time to call up heavy counterarguments, namely, the data of the experiment of Japanese scientists on photographing the hydrogen atom, which became known on November 4, 2010. The picture clearly shows the atomic shape, confirming both discreteness and roundness of atoms: “A group of scientists and specialists from the University of Tokyo photographed a single hydrogen atom for the first time in the world - the lightest and smallest of all atoms, news agencies report.
The picture was taken using one of the latest technologies - a special scanning electron microscope. Using this device, along with a hydrogen atom, a separate vanadium atom was also photographed.
The diameter of a hydrogen atom is one ten-billionth of a meter. Previously, it was believed that it was almost impossible to photograph it with modern equipment. Hydrogen is the most common substance. Its share in the entire Universe is approximately 90%.
According to scientists, other elementary particles can be captured in the same way. “Now we can see all the atoms that make up our world,” said Professor Yuichi Ikuhara. “This is a breakthrough to new forms of production, when in the future it will be possible to make decisions at the level of individual atoms and molecules.”
Hydrogen atom, conditional colors
http://prl.aps.org/abstract/PRL/v110/i21/e213001
A group of scientists from Germany, Greece, the Netherlands, the USA and France took pictures of the hydrogen atom. These images, obtained with a photoionization microscope, show the electron density distribution, which completely coincides with the results of theoretical calculations. The work of the international group is presented in the pages of Physical Review Letters.
The essence of the photoionization method is the sequential ionization of hydrogen atoms, that is, the removal of an electron from them due to electromagnetic irradiation. The separated electrons are directed to the sensitive matrix through a positively charged ring, and the position of the electron at the moment of collision with the matrix reflects the position of the electron at the moment of ionization of the atom. The charged ring, which deflects the electrons to the side, plays the role of a lens and with its help the image is magnified millions of times.
This method, described in 2004, has already been used to take "pictures" of individual molecules, but physicists have gone further and used a photoionization microscope to study hydrogen atoms. Since hitting one electron gives only one point, the researchers accumulated about 20,000 individual electrons from different atoms and averaged the image of the electron shells.
According to the laws of quantum mechanics, an electron in an atom does not have any definite position by itself. Only when an atom interacts with the external environment, an electron with one probability or another appears in a certain neighborhood of the atomic nucleus: the region in which the probability of finding an electron is maximum is called the electron shell. The new images show differences between atoms of different energy states; scientists were able to visually demonstrate the shape of the electron shells predicted by quantum mechanics.
With the help of other instruments, scanning tunneling microscopes, individual atoms can not only be seen, but also moved to the right place. About a month ago, this technique allowed IBM engineers to draw a cartoon, each frame of which is composed of atoms: such artistic experiments do not have any practical effect, but demonstrate the fundamental possibility of manipulating atoms. For applied purposes, it is no longer a atomic assembly, but chemical processes with self-organization of nanostructures or self-limitation of the growth of monatomic layers on a substrate.