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The Chemical World This Week
Chemical & Engineering
NEWS NOVEMBER 14, 1966
Orbital, structure work wins Nobel Prize for Mulliken
Next month in Stockholm, the Nobel Prize in Chemistry will be added to the burst of honors that have come in the past few years to Prof. Robert Sanderson Mulliken, 70, of the University of Chicago. The Swedish Royal Academy of Sciences chose Prof. Mulliken for the $60,000 prize for "his fundamental work concerning chemical bonds and the electronic structure of molecules by the molecular orbital method." It will be the 12th chemistry prize to be won or shared by a U.S. scientist (58 have been awarded, the first one in 1901).
Mulliken himself had this to say from Florida State University, where he is spending the winter: "I have been happy recently to see how theoretical work I have developed over some decades . . . is being applied to chemistry and biology . . . [my work] has been in brief trying to understand what the electrons are doing in molecules—how the particular behavior of electrons in particular molecules holds them-together and gives each molecule its own individual characteristics. These [electrons] are interesting in themselves just as different people are. But they also make each kind of molecule useful for various applications to human activities."
Prof. Mulliken displayed the same catholic view of electronic and human phenomena in a talk at Sanibel Island, Fla., in January 1965. The event was the International Symposium on Atomic and Molecular Quantum Theory, which was dedicated to him and later published as a special issue of the Journal of Chemical Physics 43, 10 (Part 2) (1965).
He recalled in those remarks much of the history of molecular quantum mechanics. But he recalled also the summer of 1930 and eating fried chicken in Berlin in Onkel Tom's Hutte with his wife of six months (the former Mary Helen von Noe, whom he had met in Chicago the previous summer and married on Christmas Eve) . He recalled going to the movies in Leipzig to see the classic Der Blaue Engel, whose female star, Marlene Dietrich, came later to have in common with
Mrs. Mulliken the fact that the same surgeon extracted both their appendixes. In the same paragraph with the appendix Prof. Mulliken remembered being "much impressed with the work that Beutler had been doing on inner shell excitations of atomic spectra."
By that summer of 1930, Mulliken was well into the career that had started in Newburyport, Mass., June 7, 1896, just a year before J. J. Thomson discovered the electron. He received a B.S. in chemistry in 1917 at MIT (where his father taught chemistry) and spent 1917-19 with the U.S. Bureau of Mines, the Chemical Warfare Service, and New Jersey Zinc, in that order. In the fall of 1919 he moved to the University of Chicago, where he received a Ph.D. in 1921. His thesis, under W. D. Harkins, was on the partial separation of mercury isotopes by distillation.
As a National Research Council fellow (1921-25) at Chicago and later at Harvard, Mulliken pursued his work on isotopes. But his interests shifted gradually to the effects of isotopes on line (atomic) and band (molecular) spectra. By 1925 he had started to try to understand the existing data on band spectra, using the existing quantum theory, which proved to be not quite up to the job.
That same year—1925—saw the announcement of the Pauli exclusion principle and the idea of electron spin. These partly complementary concepts meant among other things that two electrons of opposite spin could simultaneously occupy the same "orbital" (a word coined by Mulliken although not until 1932). Finally, in 1926, modern quantum mechanics came to life in different forms at almost the same time in the work of several theorists. (Also in 1926 Mulliken became assistant professor of physics at Washington Square College, New York University, where he remained until 1928.)
Friedrich Hund, in Genu any, lost no time in applying the new concepts. He made it quite clear (in 1927) that atomic spectra in principle could be understood in terms of the so-called aufbau—or building up—process, in which each electron is assigned to an orbital.
Hund and Mulliken had met in 1925
Chemical physicist Mulliken Electrons are interesting
when Mulliken first went to Europe. In the summer of 1927, when both were in Gottingen, they talked extensively about molecular spectra. Their thinking continued to develop along somewhat parallel lines.
Hund had dealt in principle with atomic spectra, but for molecular spectra the picture was not so clear. Should molecules be treated as combined atoms, formed by coalescence of their nuclei; or as the separated atoms into which they dissociate when their bond lengths grow to infinity? The answer—somewhere between these extremes—came in Mulliken's crucial papers of the following year [Phys. Rev., 32, 186,761 (1928)] .
In those papers, Prof. Mulliken applied the isoelectronic (same number of electrons) principle to molecules, as it had been applied before to atoms. Thus when two molecules, such as carbon monoxide and nitrogen, have the
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"The period from 1928 to 1963 covers the time during which most of the basic concepts and theory of molecular structure were born and grew to a vitality and vigor of their own. In the development of these principles the name of Mulliken will go down into history side by side with those of Pauling, Slater, Hund, and Lennard-Jones."
C. A. Coulson in "Molecular Orbitals in Chemistry, Physics, and Biology— A Tribute to R. S. Mulliken," Per-Olov Lowdin and Bernard Pullman, Editors, Academic Press, New York and London, 1964
same number of extranuclear electrons, those electrons should behave in the same way and should be subject to the assignment of quantum numbers. When a molecule forms, the electrons contributed by its atoms move into new patterns in molecular orbitals— and the aufbau principle applies to molecules as well as to atoms.
This work underlies almost everything that has come since in molecular structure. It destroyed the stereotype that atoms form molecules as bricks form walls, each brick retaining its original identity.
In the succeeding years, Prof. Mulliken has been building on and extending molecular orbital theory to polyatomic molecules, heteropolar di-atomics, hyperconjugation, intensities in spectra, and the theory of molecular complexes. He foresees "colossal rewards" from the use of digital computers in quantum-mechanical calculations on the structure of matter. Says colleague Michael Kasha, director of Florida State's Institute of Molecular Biophysics: "He is at the very peak of his career and during the past five years has covered as much or more research territory than during any comparable period in his life."
Since 1961, Prof. Mulliken has held a postretirement appointment as Distinguished Service Professor of Physics and Chemistry at Chicago, where he has been since 1928. For the past few years, the Mullikens have spent part of each year at FSU's Institute of Molecular Biophysics in Tallahassee, where he is Distinguished Research Professor of Chemical Physics and daughter Valerie is a freshman. A second daughter, Lucia Maria (Mrs. William W. McGrew) lives in Athens, Greece.
Prof. Mulliken, a member of the National Academy of Sciences, has received the Bronze Medal Award, Liege
(1948) ; Gilbert N. Lewis Gold Medal, ACS California Section (1960); Theodore W. Richards Gold Medal, ACS Northeastern Section (1960); ACS Peter Debye Award (1963); John Gamble Kirkwood Medal, Yale University department of chemistry and ACS New Haven Section (1964); and the Willard Gibbs Medal, ACS Chicago Section (1965).
Physics prize to Frenchman French physicist Alfred Kastler was awarded the 1966 Nobel Prize for Physics for his discovery and development of optical methods used to observe resonances in the ground and excited states of atoms. About $60,-000 goes with the citation made by the Swedish Royal Academy of Sciences, Stockholm, and to be presented next month.
Since 1941, Prof. Kastler has been teaching physics at the École Normale Supérieure in Paris, where he was once a student. His principal research has been in spectroscopy, including studies in excited states of atoms, atomic ground states, Raman spectra, spectra of the night sky, optical methods of radio-frequency spectroscopy, interferometry, and optical masers.
Long recognized for his contributions in physics, Dr. Kastler has received honorary doctorates from the universities of Louvain (Belgium), Pisa (Italy), and Oxford (England). He was made Chevalier de la Légion d'Honneur in 1952 and received the Holweck Prize of the London Physical Society in 1954. In 1957, the French Academy of Sciences awarded him its Grand Prix de la Recherche Scientifique. The Optical Society of America awarded him, in 1962, the first
Physicist Kastler Resonances in atoms
C. Ε. Κ. Mees International Medal for his work in "extending the frontiers of optics."
Dr. Kastler's career has been a combination of research and teaching. Before beginning graduate studies, he taught high school physics (1926-31) . Then he was an assistant at the University of Bordeaux while doing his thesis research on the stepwise excitation of mercury atoms. After he received his Docteur des Sciences Physiques, in 1936, for this work, he taught for two years at Clermont Fer-rand University. From 1938 to 1941, he was professor of physics at Bordeaux University.
Case, WRU merge sciences The merger of three science departments—chemistry, physics, and mathematics—at Case Institute of Technology and Western Reserve University has been approved by the trustees of the two Cleveland schools. In addition, the trustees also approved a plan for WRU's biology department (Case has none) to serve both institutions.
No timetable for formal unification of the departments has been announced. The separate department chairmen will temporarily retain their titles, and the departments will probably finish the current academic year separately. But eventually, each department will have a single chairman, and faculty for the merged departments will be jointly recruited and appointed.
In a joint statement, the presidents of the two schools, WRU's John S. Millis and Case's Robert W. Morse, said the "intent of the trustees' action was to bring into being a nationally recognized community of academic excellence, building on what has already been achieved." Planning for the development of physical facilities for the merged departments will begin immediately.
The action is not the first such collaboration between the schools—several years ago their geology and astronomy departments were merged. Nor is it likely to be the last. Both schools are undergoing a study headed by former Ford Foundation president Dr. Henry T. Heald to investigate future collaboration on a broader scale. A report on the $400,000 study is not due until June. But the merger decision was enthusiastically supported by the study commission, according to Dr. Morse and Dr. Millis.
Such joint planning is a logical outcome of, and would not be possible without, the back-to-back locations of the schools. The campuses are literally within a stone's throw of each other in Cleveland's prestigious Uni-
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