Zeeman effect (Zeeman), Peter( Nederlands physicist, Nobel Prize in Physics, 1902)
Comments for Zeeman effect (Zeeman), Peter
Biography Zeeman effect (Zeeman), Peter
May 25, 1865, Mr.. - October 9, 1943
Netherlands physicist Pieter Zeeman was born in the village Zonnemayre, in the family of the Lutheran priest Katarinusa Forandinusa Zeeman and his wife Wilhelmina (nee Vorst) Zeeman. Receiving primary education in Zonnemayre, he attended high school in Zirikzee - town, located about five miles, and then within two years he studied Latin and Greek in g. Delft, to meet the requirements necessary for entry to university. He was from a young age showed the ability in the sciences: published a report on the Northern Lights, . were common in Zonnemayre, . and impressed the Netherlands physicist Kamerlingh Onnes, . which met in Delft, . his understanding of the treatise on the theory of heat, . written by Scottish physicist James Clerk Maxwell.,
. In 1885, Mr.
. Z. enrolled in the University of Leiden, where he studied under the guidance of Onnes and theoretical physicist Hendrik Lorentz. Five years later he became assistant to the Lorentz. His experimental skill with which the study of the Kerr effect while working on his doctoral dissertation, earning him the gold medal of the Netherlands gaarlemskogo a scientific society in 1892. and his doctorate next year.
The effect, open the Scottish physicist John Kerr in 1875, was connected with the influence of magnetism on polarized light. Normal light consists of electric and magnetic fields, oscillating in the directions perpendicular to the line of distribution (both fields are interdependent and mutually perpendicular to each other). The oscillation frequency corresponds to the perceived eye color. If one of the fields oscillate predominantly in one of the many possible directions, then we say that the light is polarized in the plane defined by this preferred direction and the direction of the light beam. Kerr has found that the plane of polarized light reflected from the polished pole of a magnet rotates the plane of polarized. (Another Kerr effect is also open in 1875, consisted of birefringence arising in a transparent medium under the influence of an electric field. If you double the speed of light refraction is different in different directions in the matter, so that the incident beam is split into two different divergent beam.)
After spending a semester at the Institute of Kohlrausch in Strasbourg (France), W. returned to the University of Leiden in 1894. Assistant Professor (part-time lecturer). He again began exploring the interaction between magnetism and light. Until now, only two were known magneto-optical phenomenon: one, . observed Kerr, . and second, . which was opened by the British physicist and chemist Michael Faraday, . installed in 1845, . that the plane of polarization rotated, . when light passes through some of the body, . placed in a strong magnetic field,
. Now W. focused not on the very light, and at its source, starting with a sodium flame placed between the pole pieces of a strong electromagnet. The light from this source does not consist of all the rainbow colors (frequencies), like the light of the sun, but was made up of discrete frequencies characteristic of the material from which made the source. If the light is passed through a narrow slit and watch it (or photograph) by means of optical spectroscopy, the frequency split, which was manifested in a series of colored lines, called the spectrum. Situation of the spectral lines indicates their frequency. The spectrum of sodium has two bright yellow-orange line, and which focused Z.
The objective sought by the SZ, was connected with the electromagnetic theory, created by Maxwell in 1860-ies. and developed further by Lorentz. Maxwell theory, first showed that light consists of electromagnetic fields. Moreover, he showed that his theory predicts the speed of light, already known from numerous laboratory measurements, and found that the oscillating electric currents to emit electromagnetic radiation. His theory was confirmed by the German physicist Heinrich Hertz, who received electromagnetic waves with an electric circuit and showed that they have predicted characteristics such as speed, which coincides with the speed of light.
. Lorenz argued theory, vesting it in the concrete images of electrically charged particles (later known as electrons) in atoms or molecules, vibrating at a frequency which corresponds to the color of the light
. Since moving charged particles form an electric current, their movement should influence the magnetic field, just as in the electric motor current, interacting with the poles of a magnet, causes the rotor to turn. Z. hoping that it will change the vibration of the magnet hypothetical particles in the flame of sodium and that the changed frequency will manifest itself visually in the expansion of the spectral lines. Although convincing theory of Maxwell and other physicists impelled to act in similar directions, no one has succeeded. The first attempts to W. were also disappointing.
Later W. learned that Faraday staged a similar experiment in 1862. and failed. Feeling great respect for Faraday, SW. decided that the experiment is worth further efforts. He returned to him using the equipment, has a higher resolution, and in August 1896. observed the expected increase in the spectral lines of sodium. Since the effect was negligible, W. the question: whether 'we have succeeded in changing the period of vibration, ie. that Maxwell believed nevozmozhnym'N Even Dzh.U. Stratton (Lord Rayleigh) is not able to detect it, although he did not question the achievement of W. To remove any doubt, NW. repeated the experiment many times both in Leiden, and the University of Amsterdam, where he moved in 1897. lecturer in physics.
The experiment was particularly difficult, because it used a device - the mirror-concave diffraction grating, created in 1882 by Mr.. American physicist Dzh.X. Rowland. With a 10-foot shoulder between the mirror and the photographic plate, this device was extremely sensitive to vibrations caused by any movement in the laboratory or traffic on nearby streets. Z. frequented by more provincial Groningen University, where conditions allow a more accurate measurement.
. Lorenz predicted that the magnetic field will cause electrically charged particles of matter to another oscillate at a frequency slightly different from the corresponding frequencies for particles which have not undergone such an impact
. Thus, he expected that the spectral line is not just more, but split into three different lines. He predicted also that the light emitted will be polarized in a certain way in accordance with the changing movement of particles. Z. able to detect the predicted polarization, and after painstaking experiments with the flame during the combustion of other substances such as cadmium, he managed to split the newly increased line spectrum into separate components.
Precise measurements of W. shown that vibrating particles can not be as heavy as an atom, regarded as the English physicist Joseph Larmor. Splitting lines will undertake an assessment ratio of electric charge to the mass of vibrating particles, which proved to be surprisingly large, as well as to establish that the charge is negative. These results not only consistent with the description, which Lorenz gave his electron, but also allowed to assume that the electron is identical to the Lorentz electron, discovered in 1897. Dzh.Dzh. Thomson in the study of electrical discharges in gas-vacuum tubes. "The fact that vibrates in the light source - concluded Z., - identical to what is moving in the cathode rays'. Name of the cathode rays was given to particles moving from the negative electrode (cathode) to the positive electrode (anode) in the discharge tube. The difference was that the electrons Lorentz somehow included in the atom, have been associated with it, while the electrons Thomson is a free-moving particles in a vacuum gas tube.
Confirmation W. was the result of brilliant intuition, it has made fundamental contributions to understanding the structure of matter. The magnetic splitting of spectral lines, known as the Zeeman effect - is an important tool for studying the nature of the atom, and it is useful in determining the magnetic fields of stars. Opening of the fact, . that the spectral lines can be split into a much larger number of components, . than triplets, . as imagined Lorenz, . revealed the weakness of the then current theory, . but also gave an important impetus to the construction of quantum theory, . particularly in relation to the energy states of the atom.,
. In 1900, Mr.
. Z. was appointed professor of the University of Amsterdam. Here he devoted much of his subsequent scientific work to improve its spectral studies.
In 1902, Mr.. Nobel Prize in Physics was awarded to W. and Hendrik Lorentz 'in recognition of outstanding contributions they have made their own investigation of the influence of magnetism on radiation'. When presenting the winners Hjalmar Teel, a member of the Royal Swedish Academy of Sciences, said that the Zeeman effect 'is one of the most important experimental achievements over the past decade'. He added that 'the consequences of opening W. promise to significantly improve our knowledge about the structure of the spectra and the molecular structure of matter '.
In 1908, Mr.. Z. was appointed director of the Physics Institute at the University of Amsterdam. When in 1923. University created the new physical laboratory (later called the Zeeman Laboratory), W. was appointed its director. His subsequent work included the very difficult and precise measurements of the speed of light in moving material transparent media, such as glass and quartz (other researchers have done similar measurements in the moving water). He found that the changes depend not only on the velocity and the refractive index of the moving medium but also on the frequency of light. His results agreed with the then new theory of relativity, proposed by Albert Einstein. Z. also developed a technique of combined magnetic-electric deviation of electrically charged atoms, . to separate them according to their masses, . and opened several new isotopes (chemical elements, . whose atoms have different masses, . but the same nuclear charge).,
. married Johanna Elizabeth Lebre in 1895. They had three daughters and a son. Dignified, yet gentle man with a pleasant demeanor, he enjoyed the love and respect of his colleagues and all staff. Joint discussion of problems with the students cheering them in the laboratory. Language skills helped him to forge friendly relations with many other European physicists. Subject to the established custom, he resigned and left the University of Amsterdam in 1935, aged seventy years, eight years later he died.
In addition to the Nobel Prize, SW. received many other awards and honorary degrees, including honorary doctoral degrees at Oxford, Goettingen, Strasbourg, Glasgow, Brussels and Paris. He was awarded the Rumford Medal of the Royal Society of London, Wilde Prize of the French Academy of Sciences, Baumgartner Prize of the Austrian Academy of Sciences and the Henry Draper Medal of the American National Academy of Sciences.