Resonant energy absorption. Mössbauer effect

RESONANCE ABSORPTION

absorption of photons of frequency v \u003d (E n - E 0) / h, Where E n and E 0 are the energies of the excited and ground states of the absorbing system (for example, an atom), h - The bar is constant. R. p. Is observed in nuclear physics (see. Mössbauer effect).

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See what "RESONANCE ABSORPTION" is in other dictionaries:

resonant absorption - - [Ya.N. Luginsky, M.S.Fezi Zhilinskaya, Y.S.Kabirov. English Russian Dictionary of Electrical Engineering and Power Engineering, Moscow, 1999] Subjects of electrical engineering, basic concepts of EN resonance absorption ...

resonant absorption - rezonansinė sugertis statusas T sritis Standartizacija ir metrologija apibrėžtis Elektromagnetinių bangų, kurių dažnis lygus (arba beveik lygus) medžiagos ar terpės atomų elektronų, molekulių atomų, brandui savų nn Penkiakalbis aiškinamasis metrologijos terminų žodynas

resonant absorption - rezonansinė sugertis statusas T sritis fizika atitikmenys: angl. resonance absorption; resonant absorption vok. Resonanzabsorption, f rus. resonant absorption, n pranc. absorption par résonance, f; absorption résonante, f… Fizikos terminų žodynas

Selective absorption of g quanta by atomic nuclei due to quantum transitions of nuclei into an excited state. When irradiating in wa g quanta, along with the usual processes of taking with in vom (see GAMMA RADIATION), a radiative forcing is possible, when g ... Physical encyclopedia

resonant absorption of gamma radiation - - [A.S. Goldberg. The English Russian Energy Dictionary. 2006] Energy topics in general EN resonance gamma absorption ... Technical translator's guide

resonant neutron absorption - - [A.S. Goldberg. The English Russian Energy Dictionary. 2006] Energy topics in general EN neutron resonance absorptionresonance neutron absorption ... Technical translator's guide

resonant absorption of radiation by gas - Absorption of radiation by unexcited gas atoms (that is, those in the normal state), in which photons are completely absorbed, and the atoms pass into an excited state ... Polytechnic Terminological Explanatory Dictionary

spin resonance absorption - sukininė rezonansinė sugertis statusas T sritis fizika atitikmenys: angl. spin resonance absorption vok. Spinresonanzabsorption, f rus. spin resonant absorption, n pranc. absorption par résonance de spin, f ... Fizikos terminų žodynas

Conversion of energy el. magn. radio waves propagating in a medium into other types of energy. Distinguish between non-resonant and resonant P. p ... Physical encyclopedia

Resonant absorption of γ quanta by atomic nuclei, observed when the source and absorber of γ radiation are solid, and the energy of γ quanta is low (Mössbauer effect is 150 keV). Sometimes M. e. called resonant absorption without recoil, ... ... Great Soviet Encyclopedia

Resonant excitation of atomic levels by photons from a source from the same substance is easily observed. The situation is different for atomic nuclei. This is mainly due to the fact that the natural width Γ of the nuclear levels is small in comparison with the recoil energy R of the emitting nucleus (source) or the absorbing nucleus (target). For example, the natural width Г of the first excited level of the 57Fе nucleus located at an excitation energy E \u003d 14.4 keV is / τ \u003d 4.6 · 10 -9 eV (the measured average lifetime is τ \u003d 98 ns), while during emission and absorption it is quanta, this nucleus acquires recoil energy TR ~ E 2 / 2Ms 2 ~ 0.02 eV (where M is the mass of the 57 Fe atom).
Resonant absorption can take place only when the recoil energy of the nucleus R is less than the width of the nuclear level G. Mössbauer, investigating the phenomenon of resonant absorption of γ-quanta, lowered the temperature of the source and found that the number of absorbed photons increased significantly, that is, resonant absorption of γ-quanta was observed ... Qualitatively, this can be explained by the fact that in this case the recoil momentum was received not by an individual nucleus, but by the entire crystal, in which there were nuclei emitting γ-quanta. When passing from free atoms to atoms bound in the crystal lattice, the situation changes. As the temperature of the source decreases, the relative number of nuclear transitions with the transfer of the recoil momentum to the entire crystal increases. The conditions for this are the more favorable, the lower the crystal temperature and the transition energy E γ.
This phenomenon, called the Mössbauer effect, was immediately applied to measure the width of the levels and to check the ratio Γ \u003d / τ. To observe the resonant absorption by a 57 Fe target of γ-quanta emitted by a 57 Fe source, it is necessary to compensate for the recoil energy of the nucleus, which in total is 2T R. If we neglect the natural width of the level, then the energy of the emitted photons is equal to E γ \u003d E - T R, whereas in order for a resonance to be observed, they must have the energy E γ \u003d E + T R. One of the ways of such compensation is that the considered radioactive source is fixed on the moving device and the speed is selected so that the difference 2T R is compensated by the Doppler effect. To do this, it is enough to fix the source under study on a movable carriage and change its speed v so that due to the Doppler effect, the resonance absorption line is shifted in the desired direction. An absorber of the same isotopic composition as the source is placed between the detector and the source, as shown in Fig. 1. In the absence of recoil, resonant absorption should occur at v \u003d 0. In this case, the number of photons recorded by the detector will be minimal, since photons that have undergone resonance absorption in the absorber are then re-emitted in different directions and leave the transmitted beam. When the velocity v changes, the Doppler shift of the emission line relative to the absorption line changes and, as a result, the line contour is recorded, as shown in Fig. 2. The width of the nuclear levels is so small that the source needs to be moved at a speed of only tenths of a centimeter per second.

Atoms absorb especially intensely light of frequency corresponding to the transition from the ground state to the nearest excited state. This phenomenon is called resonant absorption. Returning then to the ground state, the atoms emit photons of the resonant frequency. The corresponding radiation is called resonant radiation or resonant fluorescence. The phenomenon of resonant fluorescence was discovered by R. Wood in 1904. Wood discovered that sodium vapor, when irradiated with light corresponding to the yellow sodium line, begins to glow, emitting radiation of the same wavelength. Subsequently, a similar glow was observed in mercury vapor and in many other cases. Due to resonant absorption, light passing through the fluorescent substance is attenuated.

Like atoms, atomic nuclei have discrete energy levels, the lowest of which is called normal, the rest - excited. The transitions between these levels lead to the appearance of short-wave electromagnetic radiation, which is called γ-rays (see § 70). It could be expected that for γ-rays there is a phenomenon of nuclear resonance fluorescence, analogous to atomic resonance fluorescence observed in visible light. However, it was not possible to observe resonant fluorescence with γ-rays for a long time. The reason for these failures is as follows. It was shown in Section 30 that the emission line and absorption line corresponding to the transition of a quantum system between two states are shifted relative to each other by where R is the recoil energy determined by formula (30.10). For visible light, the shift is many orders of magnitude smaller than the spectral line width, so that the emission and absorption lines practically overlap. The situation is different in the case of -rays. The energy and momentum of an -photon is many times greater than that of a visible light photon. Therefore, the recoil energy R is also much larger, which in this case should be written as follows:

where is the mass of the nucleus.

In γ-ray spectroscopy, it is customary to use energies instead of frequencies. Therefore, the width of the spectral line, the shift of lines, etc., we will express in units of energy, multiplying for this purpose the corresponding frequencies by Planck's constant.

In these units, the natural width of the spectral line will be characterized by the value of Г (see formula (30.2)), the shift of the emission and absorption lines - by the value, and the Doppler line broadening - by the value

(see (30.14)).

The energy of-quanta usually ranges from to (which corresponds to frequencies within and wavelengths from to). Let us calculate the recoil energy R for the case of mass of the order of 100). The value will be. Therefore, in accordance with (50.1)

and the shift of the 2R lines is.

The natural spectral line width Г is determined by formula (30.1). The typical lifetime of the excited states of nuclei is. This lifetime corresponds to

For nuclei with mass, the average speed of thermal motion at room temperature is about 300 m / s. At this speed, the Doppler linewidth c is

(see formula (50.2)).

A comparison of the values \u200b\u200bof Γ and obtained by us leads to the conclusion that the width of the spectral lines emitted by nuclei at room temperature is mainly determined by the Doppler width and is approximately 0.2 eV. For the shift of the emission and absorption lines, we got a value. Thus, even for relatively soft γ-rays with an energy of 100 keV, the shift of the emission and absorption lines turns out to be of the same order of magnitude as the spectral line width. With increasing photon energy, R grows faster (as see (50.1)) than D (which is proportional to see (50.2)). In fig. 50.1 shows a typical picture for photons, showing the relative position of the emission and absorption lines.

It is clear that only a small part of the emitted photons (their relative amount is determined by the corresponding ordinates of the emission line) can experience resonance absorption, and the probability of their absorption is small (this probability is determined by the ordinates of the absorption line).

Until 1958, it was possible to observe resonant absorption of γ-rays using devices in which the source of γ-radiation moved with a speed v towards the absorbing substance. This was achieved by placing radioactive material on the rim of a rotating disc (Fig. 50.2). The disk was inside a massive lead shield that absorbed the γ-rays. The radiation beam went out through a narrow channel and hit the absorbing substance.

A quantum counter installed behind the absorber recorded the intensity of the radiation that passed through the absorber. Due to the Doppler effect, the frequency of the radiation emitted by the source increased by where v is the speed of the source relative to the absorber. By appropriately choosing the speed of rotation of the disk, it was possible to observe resonant absorption, which was detected by a decrease in the intensity of the γ-rays, measured by the counter.

In 1958 R.L. Mössbauer investigated the nuclear resonance absorption of γ-rays (an isotope of iridium with a mass number of 191; see § 66). The energy of the corresponding transition is 129 keV, the recoil energy, and the Doppler broadening at room temperature. Thus, the emission and absorption lines partially overlap, and resonant absorption could be observed. To reduce absorption, Mössbauer decided to cool the source and absorber, calculating in this way to reduce the Doppler width and hence the line overlap. However, instead of the expected decrease, Mössbauer found an increase in resonant absorption.

Mössbauer created a setup in which the source and the absorber were placed inside a vertical tube cooled with liquid helium. The source was attached to the end of a long reciprocating rod.

Working with this setup, Mössbauer observed the disappearance of resonance absorption at linear velocities of the source on the order of several centimeters per second. The results of the experiment indicated that in the cooled year 1911 the emission and absorption lines of γ-rays coincide and have a very small width, equal to the natural width of G. This is the phenomenon of elastic (i.e., not accompanied by a change in the internal energy of the body) emission or absorption was called the Mössbauer effect.

Soon the Mössbauer effect was discovered in and for a number of other substances. The core is remarkable in that the effect is observed at temperatures up to so that there is no need for cooling. In addition, it has an extremely small natural line width.

Let us begin to clarify the physical essence of the Mössbauer effect. When a -quantum is emitted by a nucleus located at a site of the crystal lattice, the transition energy can, in principle, be distributed between a -quantum, a nucleus that has emitted a quantum, a solid body as a whole, and, finally, lattice vibrations. In the latter case, phonons will appear along with the quantum. Let's analyze these possibilities. The energy required for the nucleus to leave its place in the lattice is at least eV, while the recoil energy R does not exceed a few tenths of an electron volt. Therefore, an atom whose nucleus has emitted a quantum cannot change its position in the lattice. The recoil energy that a solid body as a whole can receive is extremely small, so it can be neglected (this energy can be estimated by replacing the mass of the nucleus with the mass of the body in (50.1)). Thus, the transition energy can be distributed only between the quantum and phonons. The Mössbauer transition occurs if the vibrational state of the lattice does not change and the quantum receives all the energy of the transition.

So, upon emission or absorption of a quantum by a nucleus located at a site of the crystal lattice, two processes can occur: 1) a change in the vibrational state of the lattice, i.e., excitation of phonons, 2) the transfer of momentum of a quantum to the lattice as a whole, without changing its vibrational state , i.e., elastic emission and absorption of a-quantum. Each of these processes has a certain probability, the value of which depends on the specific properties of the crystal, quantum energy and temperature. With decreasing temperature, the relative probability of elastic processes increases.

It is easy to show that in inelastic processes, phonons with energies of the order of - the maximum frequency of lattice vibrations, 0 - the Debye temperature should be predominantly excited; see § 48).

The wavelength corresponds to the frequency fluctuation (see the paragraph following formula (48.3)). In this case, neighboring atoms move in antiphase, which can happen when an atom emitting a γ-quantum receives all the recoil energy R and then strikes a neighboring atom. To excite longer waves (lower frequencies), it is necessary that several atoms be simultaneously set in motion at once, which is unlikely. Thus, the probability of excitation of lattice vibrations will be high, provided that the recoil energy R obtained during radioactive decay by an individual atom is equal to or greater than the phonon energy of the maximum frequency:

At. Therefore, in order to obtain measurable resonant absorption, it is necessary to reduce the probability of excitation of lattice vibrations using cooling. At. Due to this, even at room temperature, a noticeable fraction of nuclear transitions occurs elastically.

In fig. 50.3 shows typical emission and absorption spectra of γ-quanta (E is the energy of a γ-quantum,

Intensity, R is the average recoil energy).

Both spectra contain practically coinciding very narrow lines corresponding to elastic processes. These lines are located against the background of broad shifted lines caused by processes accompanied by a change in the vibrational state of the lattice. With a decrease in temperature, the background decreases, and the proportion of elastic processes increases, but never reaches unity.

The Mössbauer effect has found numerous applications. In nuclear physics, it is used to find the lifetime of excited states of nuclei (in terms of T), as well as to determine the spin, magnetic moment, and electric quadrupole moment of nuclei. In solid state physics, the Mössbauer effect is used to study the dynamics of a crystal lattice and to study the internal electric and magnetic fields in crystals.

Due to the extremely small width of the Mössbauer lines, the moving source method makes it possible to measure the energy of quanta with an enormous relative accuracy of the 15th significant digit). This circumstance was used by the American physicists Pound and Rebka to discover the gravitational redshift of the photon frequency predicted by the general theory of relativity. From the general theory of relativity it follows that the frequency of the photon should change with the change in the gravitational potential. This is due to the fact that the photon behaves like a particle with a gravitational mass equal to (see paragraph 71 of the 1st volume). Therefore, when passing in a uniform gravitational field, characterized by the strength g, the path l in the direction opposite to the direction of the force, the photon energy must decrease by Consequently, the photon energy will become equal to

where is the change in the gravitational potential. The formula we have obtained is also valid for a photon moving in an inhomogeneous gravitational field (in this case.

The light coming to the Earth from the stars overcomes the strong attractive field of these stars. Near the Earth, however, he experiences the action of only a very weak accelerating field. Therefore, all spectral lines of the stars should be slightly shifted towards the red end of the spectrum. This shift, called gravitational redshift, has been qualitatively confirmed by astronomical observations.

Pound and Rebka attempted to discover this phenomenon in terrestrial conditions. They positioned the radiation source and absorber in a high tower at a distance of 21 m from each other (Fig. 50.4).

The relative change in the energy of a photon during the passage of this distance is only

This change causes a relative shift of the absorption and emission lines and should manifest itself in a slight weakening of resonance absorption. Despite the extremely small effect (the shift was about 10-2 of the line width), Pound and Rebke were able to detect and measure it with a sufficient degree of accuracy. The result they obtained was 0.99 ± 0.05 of the predicted by theory. Thus, it was possible to convincingly prove the presence of a gravitational shift of the frequency of photons in the conditions of the terrestrial laboratory.

absorption of photons of frequency v \u003d (E n - E 0) / h, Where E n and E 0 are the energies of the excited and ground states of the absorbing system (for example, an atom), h - The bar is constant. R. p. Is observed in nuclear physics (see. Mössbauer effect).

• - photoluminescence, for which the frequency of the exciting radiation w0 practically coincides with the frequency of the photoluminescence of the atom, where and are the energies of the upper excited and lower levels ...

  Physical encyclopedia

• - selective absorption of g-quanta by atomic nuclei, caused by quantum transitions of nuclei into an excited state ...

  Physical encyclopedia

• - ...

  Physical encyclopedia

• - see Intermolecular interactions ...

  Chemical encyclopedia

• - Resonant log Log for the production of resonant sawn timber See all terms GOST 17462-84. PRODUCTS OF THE FOREST INDUSTRY. TERMS AND DEFINITIONS Source: GOST 17462-84 ...

  Dictionary of GOST vocabulary

• - el.-magn. radiation emitted by a system of bound charges, the frequency of which coincides with the frequency of the exciting light ...

  Natural science. encyclopedic Dictionary

• - the actions of the acquiring company to buy shares of the absorbed company or to sell its shares in the expectation of profit due to the difference in rates. In English: Take-over arbitrage See also: Arbitration & nbsp ...

  Financial vocabulary

• - 1.the extinguishment of rights and obligations of lesser force by rights and obligations of greater force 2 ...

  Big Dictionary of Economics

• - see Absorption ...

  Encyclopedic Dictionary of Brockhaus and Euphron

• - radiation emitted by a system of bound charges, in which the radiation frequency coincides with the frequency of the exciting light ...

  Great Soviet Encyclopedia

• - See assorbimento ...

  Five-language dictionary of linguistic terms

• - TO SWEEP, - feel, - and - you are quiet; -axened ...

  Ozhegov's Explanatory Dictionary

• - ABSORPTION, absorption, many others. no, cf. ... Action according to ch. absorb-absorb. Light absorption by a dark plate. Energy absorption ...

  Ushakov's Explanatory Dictionary

• - absorption Wed the process of action according to Ch. absorb, absorb, absorb, ...

  Efremova's explanatory dictionary

• - absorbed "...

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• - ...

  Word forms

"RESONANCE ABSORPTION" in books

Make way for the chariot! Resonant road accident involving Anatoly Barkov, Vice President of Lukoil

From the book Safety Loop: A Chronicle of Car Accidents author Gutikov Petr

Make way for the chariot! High-profile road accident involving Anatoly Barkov, vice president of Lukoil Road traffic accidents are a disaster that has been going on for more than a hundred years. No one willingly wants to become a victim of an accident. And if this happened, then the victims or their

Color absorption

From the book Light and Lighting author Kilpatrick David

Absorption of Color The colors we attribute to objects are the result of the reflected radiation that reaches our eyes. When illuminated with white light, a red brick appears red because it reflects radiation from the red part of the spectrum. He can

8. Mergers and acquisitions

From the book Headliners author Kushnir Alexander

8. Mergers and Acquisitions If you think about it, we endlessly do what we expect others to do. Ilya Lagutenko A few days after the presentation of "Meamurov" "Trolls" went to Kiev - to perform at the festival "Just Rock". It so happened that Ilya and the musicians were traveling in one

MERGERS AND ACQUISITIONS

From the book Roof. Oral history of racketeering author Vyshenkov Evgeny Vladimirovich

MERGERS AND ABSORPTIONS In the organized crime of the early 90s, there was, by and large, only one principle: who is stronger, he is right. He directly contradicted the ideology of thieves, who always said that they are judged by conscience, in truth, in a human way. Neither "Tambov" nor "Malyshev"

Absorption

From the book Soul Integration by Rachel Sal

Absorption The last three techniques are for advanced energy students only. If you are strong and relatively free of negative emotions, you may choose to absorb some of the negativity of others, temporarily, to help dispel it. In some cases

Chapter 16. Absorption

From the book Beyond Fear. Transformation of negative emotions author Trobe Thomas

Chapter 16. Absorption There are always more women than men in our seminars. One reason, I think, is that women are more likely to recognize intimacy and codependency as a challenge. Another reason is that many men have a deep wound

ABSORPTION

From the book Commander I author Shah Idris

ABSORPTION Q .: I am just turned back by the occult gibberish, which sometimes I have to listen to. Almost all of my acquaintances who are carried away by this subject disgust me. I believe that we must somehow fight against such an infection that affects our society. what

Grabbing and absorbing

From the book Mass and Power by Canetti Elias

Grasping and Absorbing The psychology of grasping and engulfing, like the psychology of food in general, has not yet been investigated at all; everything here seems self-evidently clear to us. Many mysterious processes take place here, which we do not even think about. Food is the oldest in humans, and

Absorption of photons

From the book Neutrino - a ghostly particle of an atom author Asimov Isaac

Absorbing photons Until now, neutrinos have been very similar to photons. Like a photon, a neutrino is not charged, has no mass, and always moves at the speed of light. Both particles have spin. The spin of the photon is +1 or -1, while the spin of the neutrino is +1/2 or -1/2 (the difference is not very significant). However

Takeover of Austria

From the book World War II author Utkin Anatoly Ivanovich

Absorption of Austria On the evening of February 11, 1938, in the strictest secrecy, Austrian Chancellor Schuschnigg arrived in Salzburg and crossed the German border by car to meet Hitler in Berchtesgaden. Sent by Hitler, von Papen asked the chancellor if

Absorption of competitors

From the book Russian Capital. From Demidovs to Nobels author From the book Entries from the diary in LJ (2011-2015) author Zotov Georgy Alexandrovich

Political Highlights Mar. 2nd, 2015 at 12:31 PM About Nemtsov. First of all - the earth to him in peace. Yes, I did not love him. The late Boris Efimovich came from a very favorable opposition to the Marquis with a rating of half a percent, or less - and not least of all he owes the merit

As already indicated, the discrete spectrum of спектр-radiation is due to the discreteness of the energy levels of atomic nuclei. However, as follows from the uncertainty relation (215.5), the energy of the excited states of the nucleus takes values \u200b\u200bwithin the limits Eh / t, where t is the lifetime of the nucleus in an excited state. Consequently, the smaller t, the greater the uncertainty of the energy Е of the excited state. E \u003d 0 only for the ground state of a stable nucleus (for it t). The energy uncertainty of a quantum mechanical system (for example, an atom) with discrete energy levels determines natural width of the energy level(D).For example, with an excited state lifetime of 10 -1 3 s, the natural width of the energy level is about 10 -2 eV.

The uncertainty in the energy of the excited state, due to the finite lifetime of the excited states of the nucleus, leads to nonmonochromaticity of the -radiation emitted during the transition of the nucleus from the excited state to the ground state. This non-monochromaticity is called natural line width - radiation.

In addition to the processes described above (see § 259) during the passage of -radiation in matter (photoelectric effect, Compton scattering, the formation of electron-positron pairs), in principle,

resonance effects are also observed. If the nucleus is irradiated with-quanta with an energy equal to the difference between one of the excited and ground energy states of the nucleus, then resonant absorption -radiation by nuclei:the nucleus absorbs the-quantum of the same frequency as the frequency of the -quantum emitted by the nucleus during the transition of the nucleus from the given excited state to the ground state.

For a long time, the observation of the resonant absorption of квантов-quanta by nuclei was considered impossible, since during the transition of a nucleus from an excited state with energy Einto the main (its energy is taken to be zero), the emitted -quantum has an energy E  somewhat less than E,due to the recoil of the nucleus during radiation:

where E i - kinetic recoil energy of the nucleus. On excitation of the nucleus and its transition from the ground state to the excited one with energy E -quantum must have energy E "  slightly larger than E,i.e.

where E i - the recoil energy that the -quantum must transfer to the absorbing nucleus.

Thus, the maxima of the emission and absorption lines are shifted relative to each other by an amount 2E i (Fig. 344). Using the law of conservation of momentum, according to which the momenta of the-quantum and the nucleus should be equal in the considered processes of radiation and absorption, we obtain

For example, the excited state of the iridium isotope 191 77 Ir has an energy of 129 keV, and its lifetime is of the order of 10 -10 s, so that the width of the level D 4 10 -5 eV. The recoil energy upon radiation from this level, according to (260.1), is approximately equal to 5 10 -2 eV, i.e. three orders of magnitude greater than the level width. Naturally, no resonance absorption is possible under such conditions (to observe resonant absorption, the absorption line must coincide with the emission line). It also followed from the experiments that no resonant absorption is observed on free nuclei.

Resonant absorption of -radiation, in principle, can be obtained only when compensating for the loss of energy for the recoil of the nucleus.This problem was solved in 1958 by R. Mössbauer (Nobel Prize 1961). He investigated the emission and absorption of -radiation in nuclei located in the crystal lattice, that is, in a bound state (the experiments were carried out at low temperatures). In this case, the momentum and recoil energy are transferred not to one nucleus emitting (absorbing) the -quantum, but to the entire crystal lattice as a whole. Since the crystal has a much larger mass in comparison with the mass of an individual nucleus, then, in accordance with formula (260.1), the energy losses for recoil become vanishingly small. Therefore, the processes of radiation and absorption of -radiation occur practically without energy loss (ideally elastic).

The phenomenon of elastic emission (absorption) of -quanta by atomic nuclei bound in a solid, not accompanied by a change in the internal energy of the body, is called mössbauer effectUnder the conditions considered, the emission and absorption lines of S-radiation practically coincide and have a very small width, equal to the natural width G.The Mössbauer effect was discovered on deeply cooled 191 77 Ir (with a decrease in temperature, the lattice vibrations are "frozen"), and subsequently more

than on 20 stable isotopes (for example, 57 Fe, 67 Zn, etc.).

Mössbauer armed experimental physics with a new method of measurement of unprecedented precision. The Mössbauer effect makes it possible to measure the energy (frequency) of radiation with a relative accuracy of Г / E \u003d 10 -15 -10 -17, therefore, in many fields of science and technology, it can serve as the finest "instrument" for various measurements. Now it is possible to measure the finest details of the -lines, internal magnetic and electric fields in solids, etc.

An external influence (for example, the Zeeman splitting of nuclear levels or the shift of photon energy when moving in a gravity field) can lead to a very small shift of either the absorption line or the emission line, in other words, lead to a weakening or disappearance of the Mössbauer effect. This displacement can therefore be fixed. Similarly, in laboratory conditions, such a subtle effect as the "gravitational redshift" predicted by Einstein's general theory of relativity was discovered (1960).