Misplaced Pages

#979020

64-674: BKS may refer to: BKS theory , on interaction of matter and electromagnetic radiation BKS Air Transport , UK airline 1951-1970 BKS (band) , a Canadian techno group created by radio DJ Chris Sheppard, with Hennie Bekker and Greg Kavanagh BKS, Fatmawati Soekarno Airport IATA code B. K. S. Iyengar , an Indian yoga expert Bekesbourne railway station , Kent, England, National Rail station code BKS Bharatiya Kisan Sangh , Indian organisation of farmers Station code for Bekasi railway station See also [ edit ] BKS Stal Bielsko-Biała , Polish sports club Topics referred to by

128-562: A Nobel prize), and (2) what J.V.V. regards as Slater's greatest paper, that introduced the mathematical object now called the Slater determinant . "These were some of the achievements (that led to his) election to the National Academy ... at ... thirty-one. He played a key role in lifting American theoretical physics to high international standing." Slater's doctoral students, during this time, included Nathan Rosen Ph.D. in 1932 for

192-522: A department head ... he could render his guests weak with laughter simply by counting ... in Danish." Much later, S.B. Trickey wrote "While I got to know him reasonably well, I was never able to call J.C. Slater by his given name. His seeming aloofness turned out more to be shyness." Returning in time to 1920, Slater had gone to Harvard to work for a Ph.D. with Percy Bridgman , who studied the behaviour of substances under very high pressures. Slater measured

256-457: A long time yet. In light of the experimental results, Bohr informed Charles Galton Darwin that "there is nothing else to do than to give our revolutionary efforts as honourable a funeral as possible". Bohr's reaction, too, was not primarily related to the photon hypothesis. According to Werner Heisenberg , Bohr remarked: Even if Einstein sends me a cable that an irrevocable proof of the physical existence of light-quanta has now been found,

320-625: A period in Cambridge, England, before going to Copenhagen. He did not have a happy time working with Bohr who he found domineering and regretted that his name was attached to the ill-fated Bohr-Kramers-Slater (BKS) theory . Slater already had the idea that it was the photon that carried radiation energy. As he relates: Bohr was very nice, he invited me to Christmas dinner, I told him about my [photon] ideas, he felt these were fine, “But, you see, they’re much too definite." Now we cannot have this exact conservation. We must not think too specifically about

384-488: A renunciation of strict causality before there has been a much stronger resistance against it than up to now. I cannot bear the thought that an electron exposed to a ray should by its own free decision choose the moment and the direction in which it wants to jump away. If so, I'd rather be a cobbler or even an employee in a gambling house than a physicist. It is true that my attempts to give the quanta palpable shape have failed again and again, but I'm not going to give up hope for

448-477: A theoretical study of the hydrogen molecule, and William Shockley Ph.D. 1936 for an energy band structure of sodium chloride, who later received a Nobel Prize for the discovery of the transistor. Slater, in his experimental and theoretical work on the magnetron (key elements paralleled his prior work with self-consistent fields for atoms ) and on other topics at the Radiation Laboratory and at

512-574: A variety of further approaches to molecular and atomic problems. Jens Dahl, Alfred Switendick, Jules Moskowitz, Donald Merrifield and Russell Pitzer did further work on molecules, and Fred Quelle on solids. Slater rarely included his name on the papers of SSMTG members who worked with him. Major pieces of work which he did coauthor dealt with applications of (1) group theory in band structure calculations and (2) equivalent features of linear combination of atomic orbital (LCAO) , tight binding and Bloch electron approximations, to interpolate results for

576-524: Is different from Wikidata All article disambiguation pages All disambiguation pages BKS theory One aspect, the idea of modelling atomic behaviour under incident electromagnetic radiation using "virtual oscillators" at the absorption and emission frequencies, rather than the (different) apparent frequencies of the Bohr orbits , significantly led Max Born , Werner Heisenberg and Hendrik Kramers to explore mathematics that strongly inspired

640-493: Is it stated in the BKS paper that "it seems at the present state of science hardly justifiable to reject a formal interpretation as that under consideration [i.e. the weaker assumption of statistical conservation] as inadequate". This statement may have prompted experimental physicists to improve `the present state of science' by testing the hypothesis of `statistical energy and momentum conservation'. In any case, already after one year

704-430: Is the best school for science in the country' ... 'That is why you should go to some other school. You should find out how the rest of the world is.' So I went to Princeton. ... Slater was right. And I often advise my students the same way. Learn what the rest of the world is like. The variety is worthwhile." From the memoir by Philip Morse: "He contributed significantly to the start of the quantum revolution in physics; he

SECTION 10

#1732765955980

768-839: The Bell Laboratories and in association with the MIT Radiation Laboratory , was significant in the development of radar . In 1950, Slater founded the Solid State and Molecular Theory Group (SSMTG) within the physics department. The following year, he resigned the chairmanship of the department and spent a year at the Brookhaven National Laboratory of the Atomic Energy Commission. He was appointed Institute Professor of Physics and continued to direct work in

832-540: The Institute of Physics in Copenhague to “fly its flag at half mast on the anniversary of the publication of the work of Bohr, Kramers and Slater.” As suggested by a letter to Max Born , for Einstein, the corroboration of energy and momentum conservation was probably even more important than his photon hypothesis: Bohr's opinion of radiation interests me very much. But I don't want to let myself be driven to

896-616: The University of Copenhagen , where "he explained to Bohr and Kramers his idea (that was) a sort of forerunner of the duality principle , (hence) the celebrated paper" on the work that others dubbed the Bohr-Kramers-Slater (BKS) theory . "Slater suddenly became an internationally known name.". Interest in this "old-quantum-theory" paper subsided with the arrival of full quantum mechanics, but Philp M. Morse's biography states that "in recent years it has been recognized that

960-411: The 1962 President's Report, Jay Stratton wrote (on p. 17) "A faculty committee under the chairmanship of Professor John C. Slater has taken primary responsibility for planning the facilities in the new Center for Materials. These include a new Cooperative Computing Laboratory completed this year and equipped with an I.B.M. 709 Computer". The name Center for Materials Science and Engineering (CMSE)

1024-507: The BKS theory was disproved by coincidence methods studying correlations between the directions into which the emitted radiation and the recoil electron are emitted in individual scattering processes. Such experiments were carried independently, with the Bothe–Geiger coincidence experiment performed by Walther Bothe and Hans Geiger , as well as the experiment by Compton and Alfred W. Simon. They provided experimental evidence pointing in

1088-612: The Bell Laboratories did "more than any other person to provide the understanding requisite to progress in the microwave field", in the words of Mervin Kelley, then head of Bell Labs, quoted by Morse. Slater' publications during the war and the post-war recovery include a book and papers on microwave transmission and microwave electronics, linear accelerators , cryogenics , and, with Francis Bitter and several other colleagues, superconductors , These publications credit

1152-536: The English Department at the University of Rochester, which would also be Slater's undergraduate alma mater. Slater's youthful interests were with things mechanical, chemical, and electrical. When Slater entered the University of Rochester in 1917 he took physics courses and as a senior assisted in the physics laboratory and did his first independent research for a special honors thesis, a measurement of

1216-643: The SSMTG until he retired from MIT in 1965, at the mandatory retirement age of 65. He then joined the Quantum Theory Project of the University of Florida as research professor, where the retirement age allowed him to work for another five years. The SSMTG has been regarded as the precursor of the MIT Center for Materials Science and Engineering (CMSE). His scientific autobiography and three interviews present his views on research, education and

1280-458: The basis of ongoing work by Kramers to describe "dispersion" (in present-day terms inelastic scattering ) of light by means of a classical theory of interaction of radiation and matter. But abandoning the concept of the photon, they instead chose to squarely accept the possibility of non-conservation of energy, and momentum. In the BKS paper the Compton effect was discussed as an application of

1344-400: The body was the quantum to be considered. Max Planck said in 1911, Mr. Einstein, it would be necessary to conceive … [of] light waves themselves as atomistically constituted, and hence to give up Maxwell's equations. This seems to me a step which in my opinion is not yet necessary…. I think that first of all one should attempt to transfer the whole problem of the quantum theory to the area of

SECTION 20

#1732765955980

1408-432: The compressibility of common salt and ten other alkali halides—compounds of lithium, sodium, potassium and rubidium, with fluorine, chlorine and bromine. He described the results as "exactly in accord with Bohr's recent views of the relation between electron structure and the periodic table". This brought Slater's observation concerning the mechanical properties of ionic crystals into line with the theory that Bohr had based on

1472-472: The computer-aided design team of Ross , Coons and Mann, (3) members of the Laboratory for Nuclear Science, (4) Charney and Phillips in theoretical meteorology, and (5) Simpson and Madden in geophysics (from 1964 President's report, p. 336-337). In 1926, he had married Helen Frankenfeld. Their three children (Louise Chapin, John Frederick, and Clarke Rothwell) all followed academic careers. Slater

1536-529: The correct ideas in the article are those of Slater." Slater discusses his early life through the trip to Europe in a transcribed interview. Slater joined the Harvard faculty on his return from Europe in 1925, then moved to MIT in 1930. His research papers covered many topics. A year by year selection, up to his switch to work relating to radar includes: In his memoir, Morse wrote "In addition to other notable papers ... on ... Hartree's self-consistent field ,

1600-459: The dependence on pressure of the intensities of the Balmer lines of hydrogen. He was accepted into Harvard graduate school, with the choice of a fellowship or assistantship. He chose the assistantship, during which he worked for Percy W. Bridgman . He followed Bridgman's courses in fundamental physics and was introduced into the then-new quantum physics with the courses of E. C. Kemble. He completed

1664-416: The direction of energy and momentum conservation in individual scattering processes (at least, it was shown that the BKS theory was not able to explain the experimental results). More accurate experiments, performed much later, have also confirmed these results. Commenting on the experiments, Max von Laue considered that “physics was saved from being led astray.” From the very beginning, Wolfgang Pauli

1728-430: The end of his life. John C. Slater John Clarke Slater (December 22, 1900 – July 25, 1976) was an American physicist who advanced the theory of the electronic structure of atoms, molecules and solids. He also made major contributions to microwave electronics. He received a B.S. in physics from the University of Rochester in 1920 and a Ph.D. in physics from Harvard in 1923, then did post-doctoral work at

1792-537: The energy levels of solids, obtained by more accurate methods, A partial list of members of the SSMTG (Ph.D. students, post-doctoral members, research staff and faculty, in some cases successively, labeled †, ‡, ৳, ¶), together with references that report their SSMTG and later activities, follows. Distinguished visitors included Frank Boys , Alex Dalgarno , Ugo Fano , Anders Fröman, Inga Fischer-Hjalmars , Douglas Hartree , Werner Heisenberg , Per-Olov Löwdin , Chaim Pekeris , Ivar Waller and Peter Wohlfarth . In

1856-485: The following elements of a theory of emission and absorption of radiation by atoms, to be developed during his stay in Copenhagen: This fourth point reverts to Max Planck 's original view of his quantum introduction in 1900. Planck also did not believe that light was quantized. He believed that a black body had virtual oscillators and that only during interactions between light and the virtual oscillators of

1920-678: The group's research efforts." Nesbet continued "Every morning in SSMTG began with a coffee session, chaired by Professor Slater, with the junior members seated around a long table ... Every member of the group was expected to contribute a summary of his own work and ideas to the Quarterly Progress Report". The SMMTG QPRs had a wide distribution to university and industrial research libraries, and to individual laboratories. They were quoted widely for scientific and biographical content, in journal articles and government reports and libraries are starting to put them online. To begin

1984-408: The groups maintained a productive liaison. In the words of Robert Nesbet: "Slater founded the SSMTG with the idea of bringing together a younger generation of students and PostDocs with a common interest in the electronic structure and properties of atoms, molecules and solids. This was in part to serve as a balance for electronic physics to survive the overwhelming growth of nuclear physics following

BKS - Misplaced Pages Continue

2048-445: The idea of " statistical conservation of energy and momentum" in a continuous process of scattering of radiation by a sample of free electrons, where "each of the electrons contributes through the emission of coherent secondary wavelets". Although Arthur Compton had already given an attractive account of his experiment on the basis of the photon picture (including conservation of energy and momentum in individual scattering processes),

2112-546: The interaction between matter and radiation.” Independently, Franz S. Exner had also suggested the statistical validity of energy conservation in the same spirit as the second law of thermodynamics . Erwin Schrödinger , who did his habilitation under the supervision of Exner, was very supportive of the BKS theory. Schrödinger published a paper to provide his own interpretation of the BKS statistical interpretation. Slater's main intention seems to have been to reconcile

2176-399: The light beam behaves as light-quanta and that energy and momentum are conserved, Niels Bohr was still resistant against quantized light, even repudiating it in his 1922 Nobel Prize lecture. So Bohr found a way of using Einstein's approach without also using the light-quantum hypothesis by reinterpreting the principles of energy and momentum conservation as statistical principles. Thus, it

2240-751: The many other scientists, mathematicians and engineers who participated. Among these, George H. Vineyard received his Ph.D. with Slater in 1943 for a study of space charge in the cavity magnetron. Later, he became director of the Brookhaven National Laboratory and President of the American Physical Society. The work of the Radiation Laboratory paralleled research at the Telecommunications Research Establishment in England and

2304-400: The message cannot reach me, because it has to be transmitted by electromagnetic waves. For Bohr the lesson to be learned from the disproof of the BKS theory was not that photons do exist, but rather that the applicability of classical space-time pictures in understanding phenomena within the quantum domain is limited. This theme would become particularly important a few years later in developing

2368-410: The notion of complementarity . According to Heisenberg, Born's statistical interpretation also had its ultimate roots in the BKS theory. Hence, despite its failure the BKS theory still provided an important contribution to the revolutionary transition from classical mechanics to quantum mechanics. Schrödinger would not abandon the statistical interpretation and would continue to push this theory until

2432-467: The paper, they invited me to sign it, take it or leave it. This was my experience with Mr. Bohr and Mr. Kramers. Since then, it has developed in a very interesting way, namely, that I was right and they were wrong. They didn’t realize this until Mr. Bothe came along with his experiment showing that the photons were really there. So I completely failed to make connection with Bohr. I could have made connections with Kramers if it hadn’t been for Bohr, but Kramers

2496-420: The photons. We don’t have photons like that.” In other words, he wanted to make the whole thing just as vague as he could. Kramers was always Bohr‘s “yes-man” and wanted to do exactly the same thing. He said “This is a fine idea, if we will modify it in such and such ways.” That was the last I saw of it. Bohr and Kramers wrote the paper, they invited me to sign it, the letter to Nature was the first paragraph out of

2560-526: The quantum mechanical derivation of the Rydberg constant , and the best values of atomic shielding constants , he wrote a seminal paper on directing valency " (what became known, later, as linear combination of atomic orbitals ). In further comments, John Van Vleck pays particular attention to (1) the 1925 study of the spectra of hydrogen and ionized helium, that J.V.V. considers one sentence short of proposing electron spin (which would have led to sharing

2624-812: The role of science in society. Slater was nominated for the Nobel Prize , in both physics and chemistry, multiple times, and he received the National Medal of Science in 1970. In 1964, Slater and his then-92-year-old father, who had headed the Department of English at the University of Rochester many years earlier, were awarded honorary degrees by that university. Slater's name is part of the terms Bohr-Kramers-Slater theory , Slater determinant and Slater orbital . Slater's father, born in Virginia, who had been an undergraduate at Harvard, became head of

BKS - Misplaced Pages Continue

2688-403: The same term [REDACTED] This disambiguation page lists articles associated with the title BKS . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=BKS&oldid=1234352159 " Category : Disambiguation pages Hidden categories: Short description

2752-523: The same year, the CMSE staff included 55 professors and 179 graduate students. The Center continues to flourish in the 21st century. The Cooperative Computing Laboratory (CCL) was used, in its first year by some 400 faculty, students and staff. These included (1) members of the SSMTG and the CCL running quantum mechanical calculations and non-numeric applications directed by Slater, Koster, Wood and Barnett, (2)

2816-497: The sections about the department, that Slater wrote. These include statements affecting policies in physics education and research at large, and show his deep commitment to both. Throughout his Chairmanship, Slater taught, wrote books, produced ideas of major scientific importance, and interacted with colleagues throughout the local, national and international scientific communities. At the personal level, Morse states: "Through most of (the 1930s) he looked more like an undergraduate than

2880-466: The spectroscopy of gaseous elements. He wrote the alkali halide paper in 1923, having "by the summer of 1922" been "thoroughly indoctrinated ... with quantum theory", in part by the courses of Edwin Kemble following a fascination with Bohr's work during his undergraduate days. In 1924, Slater went to Europe on a Harvard Sheldon Fellowship. After a brief stay at the University of Cambridge , he went on to

2944-428: The subsequent development of matrix mechanics , the first form of modern quantum mechanics . The provocativeness of the theory also generated great discussion and renewed attention to the difficulties in the foundations of the old quantum theory. However, physically the most provocative element of the theory, that momentum and energy would not necessarily be conserved in each interaction but only overall, statistically,

3008-413: The two conflicting models of radiation, viz. the wave and particle models . He may have had good hopes that his idea with respect to oscillators vibrating at the differences of the frequencies of electron rotations (rather than at the rotation frequencies themselves) might be attractive to Bohr because it solved a problem of the latter's atomic model , even though the physical meaning of these oscillators

3072-450: The universities of Cambridge (briefly) and Copenhagen . On his return to the U.S. he joined the physics department at Harvard. In 1930, Karl Compton , the president of MIT , appointed Slater as chairman of MIT's department of physics. He recast the undergraduate physics curriculum, wrote 14 books between 1933 and 1968, and built a department of international prestige. During World War II, his work on microwave transmission, done partly at

3136-409: The war" . George F. Koster soon completed his Ph.D., joined the faculty, and became the senior member of the group. He wrote "During the fifteen-year life of the group some sixty persons were members and thirty-four took doctoral degrees with theses connected with its work. In my report I have been unable to separate the work of Slater from that of the group as a whole. He was part of every aspect of

3200-569: The work for the Ph.D. in three years by publishing his (1924) paper Compressibility of the Alkali Halides , which embodied the thesis work he had done under Bridgman. His heart was in theory, and his first publication was not his doctor's thesis, but a note (1924) to Nature on Radiation and Atoms. After receiving his Ph.D., Slater held a Hamard Sheldon Fellowship for study in Europe. He spent

3264-628: The work of the group, Slater "distilled his experience with the Hartree self-consistent field method" into (1) a simplification that became known as the Xα method, and (2) a relationship between a feature of this method and a magnetic property of the system. These required computations that were excessive for "pencil and paper" work. Slater was quick to avail the SSMTG of the electronic computers that were being developed. An early paper on augmented plane waves used an IBM card programmed calculator. The Whirlwind

SECTION 50

#1732765955980

3328-556: Was a congenial one, with main emphasis on solid state physics, statistical physics and related fields. It reminded me of the MIT department in the days when I had been department head there. It was a far cry from the MIT Physics Department which I was leaving; by then it had been literally captured by the nuclear theorists." Slater published to the end of his life: his final journal paper, published with John Connolly in 1976,

3392-403: Was a good chairman." The following items from the successive issues of the annual MIT President's Report trace the growth and visibility of the Department under Slater's leadership, before World War II, and the ability of the department to contribute to defense during the war. The first two quotations are from chapters written by Compton in the successive reports. The other quotations come from

3456-502: Was adopted soon afterward. It embodied the ethos of interdepartmental research and teaching that Slater had espoused throughout his career. The first director was R.A. Smith, previously head of the physics division of the Royal Radar Establishment in England. He, Slater and Charles Townes , the provost, had been in close acquaintance since the early years of World War II, working on overlapping topics. The center

3520-543: Was completely playing Bohr’s game. On the plus side, Slater's name was now well known by association with Bohr. On returning to America, Slater joined the Harvard Physics Department. When he became president of MIT, Karl Compton "courted" Slater to chair the physics department. "Administration (of the Department) took up a good deal of time, more time than he (Slater) would have preferred. John

3584-427: Was divorced and in 1954 he married Rose Mooney , a physicist and crystallographer, who moved to Florida with him in 1965. At the University of Florida (Gainesville) where the retirement age was 70, Slater was able to enjoy another five years of active research and publication as a research professor in the Quantum Theory Project (QTP). In 1975, in his scientific autobiography, he wrote: "The Florida Physics Department

3648-466: Was extremely critical of the BKS theory, referring to it as the Copenhagen putsch ( German : Kopenhagener Putsch ). In a letter to Kramers, Pauli said that Bohr would have abandoned the theory even if no experiment was ever carried out, arguing that it is the notion of motion and forces that needs to be modified, not the conservation of energy. Pauli could not help to mock the theory, proposing to

3712-421: Was far from clear. Nevertheless, Bohr and Kramers had two objections to Slater's proposal: As Max Jammer puts it, this refocussed the theory "to harmonize the physical picture of the continuous electromagnetic field with the physical picture, not as Slater had proposed of light quanta, but of the discontinuous quantum transitions in the atom." Bohr and Kramers hoped to be able to evade the photon hypothesis on

3776-408: Was in 1924 that Bohr, Hendrik Kramers and John C. Slater published a provocative description of the interaction of matter and electromagnetic interaction, historically known as the BKS paper that combined quantum transitions and electromagnetic waves with energy and momentum being conserved only on average. The initial idea of the BKS theory originated with Slater, who proposed to Bohr and Kramers

3840-563: Was on a novel approach to molecular orbital theory. Slater died in Sanibel Island, Florida in 1976. Slater's concern for others is illustrated by a dialog that Richard Feynman relates. It took place at the end of Feynman's undergraduate days at MIT, when he wanted to stay on to do a Ph.D. "When I went to Professor Slater and told him of my intentions he said: 'We will not have you here'. I said 'What?' Slater said 'Why do you think you should go to graduate school at MIT?' 'Because it

3904-413: Was one of the very few American-trained physicists to do so. He was exceptional in that he persisted in exploring atomic, molecular and solid state physics, while many of his peers were coerced by war, or tempted by novelty, to divert to nuclear mysteries." To paraphrase John Connolly, it can be said that the contributions of John C. Slater and his students in the SSMTG and the Quantum Theory Project laid

SECTION 60

#1732765955980

3968-502: Was set up, in accordance with Slater's plans. It "supported research and teaching in Metallurgy and Materials Science, Electrical Engineering, Physics, Chemistry and Chemical Engineering", and preserved MIT as a focus for work in solid state physics. By 1967, two years after Slater left, the MIT Physics Department "had a very, very small commitment to condensed matter physics" because it was so "heavily into high energy physics." But in

4032-478: Was soon shown to be in conflict with experiment. Walther Bothe won the Nobel Prize in Physics in 1954 for the Bothe–Geiger coincidence experiment that experimentally disproved BKS theory. When Albert Einstein introduced the light quantum ( photon ) in 1905, there was much resistance from the scientific community. However, when in 1923, the Compton effect showed the results could be explained by assuming

4096-917: Was used heavily, then the IBM 704 in the MIT Computation Center and then the IBM 709 in the Cooperative Computing Laboratory (see below). Solid state work progressed more rapidly at first in the SSMTG, with contributions over the first few years by George F. Koster, John Wood, Arthur Freeman and Leonard Mattheis. Molecular and atomic calculations also flourished in the hands of Fernando J. Corbató , Lee Allen and Alvin Meckler. This initial work followed lines largely set by Slater. Michael Barnett came in 1958. He and John Wood were given faculty appointments. Robert Nesbet, Brian Sutcliffe, Malcolm Harrison and Levente Szasz brought in

#979020