Polanyi (Polanyi), John C.( Canadian chemist, Nobel Prize in Chemistry, 1986)
Comments for Polanyi (Polanyi), John C.
Biography Polanyi (Polanyi), John C.
genus. January 23, 1929
Canadian chemist John Charles Polanyi (Polanyi) was born in Berlin, the son of Hungarian descent, Michael Polanyi and Magda Elizabeth (Kemeny) Polanyi. When the boy was four years old, the family moved from Germany to England, in Manchester, where his father became a professor of chemistry at Manchester University.
Receiving primary and secondary education at the Manchester School, P. in 1946. enrolled in the University of Manchester, and managed to listen to lectures on the chemistry of his father, who soon left the chemistry department, becoming at the same university professor of philosophy.
Colleagues father P. Chemical faculty were largely supporters of the study of simple chemical reactions, based on the molecular basis. One of the former students of Polanyi senior Ernst Uorarst became the scientific leader P. Subject Uorarsta doctoral dissertation was related to the experiments that were carried out using the device with a sodium flame. These experiments have allowed my father P. and his colleagues to determine the likelihood as to whether the reaction of sodium atom with the collision of a molecule or not. Under the leadership Uorarsta P. measured the energy of chemical bonds by pyrolysis (decomposition by heat). In 1952, Mr.. scientist received his doctorate in chemistry.
In the years spent in the University of Manchester, determine the direction of future work P. on the molecular basis of chemical reactions. The University of Manchester focused on the unresolved problem of absolute reaction rates, ie. the question of whether an encounter certain molecular forces to the formation of new chemical. P. reoriented this task to the question of what types of forces most often give rise to reactions. He decided, . the answer to this question is easiest to find, . studying the movement of newly emerged reaction products, . as forces, . operating in the 'transition state' (from the moment, . when reagents are in contact, . until the reaction products), . can not leave a mark on the products of the reaction.,
. After defending his doctoral thesis work in 1952 ... 1954
. with E.U.R. Stacy in the laboratories of the State Scientific Research Council of Canada in Ottawa, P. more and more convinced that it is properly raised the issue and that he should be sought answer to it. Can not say that in his student years spent in England, a scientist felt a calling to his chosen profession. His main interests, rather, lay in the field of politics, journalism and poetry. Interest in science was somewhere in the background. The sunny climate of Ottawa, however, woke up in the scientific thirst for creativity: P. enthusiastically took up the laboratory work. Along with Stacy, he decided to check, . whether the 'prophetic power' then dominant transition state theory reaction rates, . and, . Having some calculations, . concluded, . that this theory is unsubstantiated, . because it said nothing about the forces, . operating in the transition state,
. A few months from two years, . held at the State Research Council, . He worked in the laboratory of Gerhard Herzberg, . where he assembled a spectroscopic setup for testing the vibrational and rotational excitation of iodine molecules,
. 'I must have sent some invisible hand', - recalled P. about this period later. And indeed, later the scientist had a chance to measure the reaction products exactly the kind of transition, which he studied in the laboratory Herzberg.
Then P. at the invitation of the American chemist Hugh Stott Taylor worked for two years at Princeton University in the U.S. on a scholarship, selected him as the Doctor of Science for research. Here he met with two colleagues Taylor - - Michael Baudartom and David Garvin, who investigated the vibrational excitation in the products of the reaction of atomic hydrogen with ozone. When this reaction was observed an orange glow when the reaction product spontaneously transition from highly excited vibrations to a very low state of excitation. Despite the fact that P. not participate in these experiments, they have had a great influence. The relatively high frequency radiation (high overtones) of these vibrational transitions turned the P. the thought of the possibility of detection is much more likely 'fundamental transitions', caused by smaller changes in the vibrational state, in which shall be observed infrared radiation at frequencies. Returning in 1956. to Canada to lecture on chemistry at the University of Toronto, P. not forgotten this fall at Princeton, his idea.
. Together with the students their first release, scientists have observed an increase in the rate of formation of hydrogen chloride in the vibrational excitation of the exothermic reaction (in which heat is released) of atomic hydrogen and molecular chlorine
. Experience with hydrogen chloride, reported that first appeared in 1958, helped P. and his team choose the direction of their main work.
This experiment was simple and cheap. Atomic hydrogen, . formed by electric discharge (with the use of neon transformer for high voltage), . low-pressure mixed with a stream of chlorine gas in the vessel, . equipped with 'windows' of sodium chloride, . transparent in the infrared region,
. Before the 'window' was placed infrared spectrometer. Vessel in which the reaction took place, remained cool to the touch, but gave the infrared spectrum, which indicated the presence of hydrogen at a temperature of several thousand degrees. This molecular excitation was chemical in nature and was an infra-red chemiluminescence.
In 1958, Mr.. P. and his student, JK. Keshion finished their message made the statement that 'through this method can obtain information regarding the distribution of vibrational and possibly rotational energy among the products of three-center reaction. And this kind of information - only the first of those opportunities that this method before chemists'.
However, their pledge was fulfilled only 10 years later. Was a big job, which was attended by students P. many issues. One of the problems hindering the investigation, was in the vibrational and rotational 'damping'. This problem was solved through the use of spraying gaseous reactants, which intersect in the center of an evacuated chamber, emitting infrared radiation, accompanying the formation of reaction products. Then eliminates the products of condensation on the walls of the chamber, cooled by liquid nitrogen, before they had time to relax (to come to the ground state). This interrupted relaxation led to the first quantitative definitions of 'detailed rate constants', ie. velocity at which the reaction products formed with the specific vibrational and rotational states and, therefore, translational (portable) excitation.
. Measurements, . relating to translational excitation, . laid the foundation for the development of two methods - the method of infrared chemiluminescence Polanyi and research method of intersecting molecular beams, . This is the main alternative means of carrying out such measurements,
. Method of intersecting molecular beams, which originally measured quantities are the translational and angular distribution, was opened Dudley P. Hershbahom and Ian Lee in 1967
Major technological calculations carried P. research described in his paper 'infrared maser based on the vibrational excitation' ( 'An Infrared Mazer Dependent on Vibrational Excitation'), written in 1960. However, 'Fizikal Review leters' ( 'Physical Review Letters'), where P. submitted this article, refused to publish it as a lack of scientific interest. In this article, P. developed the idea put forward in 1958. Charles X. Townes and Arthur L. Schawlow, which later led to the creation of the laser. Townes and Schawlow provide electronic excitation Wednesday. P. also suggested that among created vibrational and rotational excitation of molecules. His proposal has some attractive aspects. First, thanks to the phenomenon, which is P. called partial inversion of the population, an active laser medium can be created simply by partial cooling of hot gas. Secondly, the active medium can be generated through chemical reaction, such a method is now known as a chemically pumped laser. Moreover, P. suggested that such lasers must exist in nature in the upper atmosphere.
'Fizikal Review leters' is not printed and the report of the American physicist Theodore X. Meumann the first the laser on the same basis, which put forward, refusing to publish the article P. When P. learned about this, he in September 1960. conveyed his story without any changes were in the 'Journal of Chemical Physics' ( 'Journal of Chemical Physics'). And there it was immediately published. Since the vibrational (developed CH.K.N. Patel), in particular chemical, lasers (developed Dzh.Ch. Paymantelom) became the most powerful source of infrared radiation. Talking with the funding basic research sponsors, who insist on proof of the possibility of practical application of scientific discoveries, P. happy to ask them about whether they would have been so far-sighted, to subsidize research barely detectable luminescence, seeing it as a way to develop the most powerful of the presently existing lasers.
. Despite its simplicity, infrared chemiluminescence gives a most complete, detailed and accessible information about the energy distribution of products of chemical reactions
. This information is used to test theories of the molecular mechanism of simple exchange reactions. The research team, led by MP, from the outset of their experiment used computer modeling. High-speed computers allow to solve complex equations of motion of reacting particles, and the connection between theory and practice opened up the opportunity to look deeply into the essence of the processes. Infrared chemiluminescence is not limited to measuring the degree of excitation of the reaction products. It can also be used to determine how the vibrational and rotational excitation of different reagents affects the probability of reactions.
In 1986. P. with Dudley P. Hershbahom and Ian Lee were awarded the Nobel Prize in Chemistry for contributions made in the 'development of a new field of research in chemistry - the dynamics of chemical reactions'. P. was marked as the author of 'method of infrared chemiluminescence, . which measures and analyzes the extremely weak infrared radiation of newly formed molecules', . and as a scientist, . Apply 'this method to clarify the problem of releasing energy in the course of chemical reactions'.,
. In recent years the scope of scientific interests P
. expands. It deals with spectroscopy of the reaction transition state in an effort to gain insight into the 'molecular dance', observing the molecules involved in it at a time when they, as P. metaphorically defines the process, are 'on stage, not backstage, just before the dance and after its completion'. Group P. also examines the photochemistry of absorbed state, using ultraviolet laser radiation to induce a reaction between neighboring molecules, clinging to a solid surface. Group hopes that it will, by placing a molecule on any predetermined pattern, to encourage them to react a certain way.
In the late 50-ies. P. came to believe that scientists should take part in public life, especially in an age of nuclear weapons, when the acute problem of survival. In 1960, Mr.. P. became the founder and chairman of the Canadian group of scientists, a member of the Pugwash movement, and remained its chairman until 1978. P. - An active member of the Committee on International Security of the National Academy of Sciences of the United States and the Canadian Center for Arms Control and Disarmament.
P. actively participates in the Royal Society, the Canadian committee on academic freedom, as well as the Canadian Committee of Scientists. He finds time to participate in the 'Canadian debates on science policy'. P. believes that only fundamental science can contribute to the future development of mankind, and the reproach of the impracticality of purely theoretical research says: 'There is nothing impractical science-oriented needs of today only'.
. In 1958, Mr.
. P. married Anne Ferrar Davidson from Toronto, musician and music teacher. In the couple's daughter and son. P. considers himself "ignorant in music ', but receives an aesthetic pleasure from art, literature and poetry. He and his wife, respectively, roles, write words and music for professionally performed humorous skits. In his youth, a scientist keen on canoeing, was pilot-lover of high class, but now he prefers ski and pedestrian walks.
In addition to the Nobel Prize, P. received many awards, including the Marlow Medal of the Faraday Society (1962), Stacey Prize in Natural Sciences (1965), Henry Marshall TOUR Medal of the Royal Society of Canada (1977) and Wolf Prize (1982). He has repeatedly confessed to leading lecturers. The scientists were awarded honorary degrees from 12 universities in Canada and 2 leading U.S. academic institutions - Harvard University and the Polytechnic Institute Ronsselerovskim. In 1974 and in 1979. P. became a knight of the Order of Canada, different degrees. He is a member of the Canadian and the Royal Society, foreign member of the American Academy of Arts and Sciences, the American National Academy of Sciences and the Pontifical Academy of Sciences in Rome.