Acknowledgement: Special thanks to Megan Matsen Meisenbach,
In Memoriam
Frederick Albert Matsen Jr., Professor Emeritus of Chemistry and Biochemistry and of Physics, died on May 30, 2006. He was 92. Matsen was born in Racine, WI in 1913 to Frederick Albert and Carrie Iversen Matsen. Albert and Carrie were Danish immigrants arriving in the United States in 1910 and 1909 respectively. They were married in 1910. Albert was a barber who owned his own shop. Danish was the language spoken in the home. On the 24 of April 1927, Albert and Carrie had their son Frederick Albert Matsen, confirmed into Gethsemane Luthern Church of Racine, Wisconsin.
Al Jr. attended Fratt Elementary School, established 1916, with many children from the largely Danish community. In its mission statement, the school placed emphasis on learning to read, stressing that "everything we do and every subject we teach hinges on the ability of our children to interpret the printed word." Al read all the books in the children section of the library and was given special permission to check out high school and adult books. Washington Park High School opened in 1929 and provided Al his secondary education. Because of the hard economic times, Al didn’t think college was possible, however, a friend and tennis pal, Paul Wehrle, was commuting to a small religious college and offered Al a ride. While studying sciences courses with an instructor, it became clear to the instructor that Al needed teachers with more scientific knowledge and strongly encouraged him to enroll at the University of Wisconsin, which he did. He was an undergraduate member of Farrington Daniel's research group. Albert Sherman, a postdoc member of the group, gave a series of informal lectures which provided “a marvelous introduction to the subject of quantum chemistry” (Al’s words). Sherman had just finished writing (with J. H. Van Vleck) The Quantum Theory of Valence [Reviews of Modern Physics 7, 167 (1935)]. The following quotation from this article, especially the final sentence, made a lasting impression on Al:
"Actually the only forces between spins are magnetic forces
which are exceedingly small, and the only reason that spin
figures in the answer is that the constraints imposed by the
Pauli principle correlate different spin alignments with different
electrostatic exchange energies.
Thus spin is only an indicator ... "
He received his BS in chemistry from Wisconsin in 1937. Sherman had studied with Henry Eyring at Princeton, so it was natural that Al would do the same. He recalls vividly George Kimball's outstanding seminar entitled “Group Theory of Directed Valence.” He was awarded his PhD in chemistry and physics in 1941.
Dr. Matsen’s career began at Bucknell University where he was an instructor from 1940–42. In 1943, he came to the University of Texas where he remained until his retirement in 1988. His first research was on the theory of liquids. In 1945, he spent one year at the University of Chicago working with Robert Mulliken, Clemens Roothaan, and John Platt. Al developed a spectral theory that was good enough to impress Linus Pauling, who, as a member of the Guggenheim Committee, was responsible for his working with Professor Charles Coulson at King's College London and Oxford in 1951–1952. In 1955, the University of Texas acquired an IBM 650 computer on which Matsen, J. C. Browne and others made many calculations. Matsen’s Quantum Chemistry Integrals and Tables were computed on this machine. Matsen was a consultant for Exxon Houston and New Jersey for over 35 years. In his Reminiscences (see at end of this page) he relates a story “Amusingly, I had been lecturing at an unnamed university on the unitary group formulation of the manybody theory. I apparently went way over the listeners' heads since the only question I got was, What possible use could you be to Exxon?”
Doug Klein, a Matsen postdoc and professor at Texas A&M University at Galveston, relates a story he heard from Matsen: “In the early 1950s, Matsen was called up to the President's office in the Tower, whence it turned out that the President complained to Matsen about Matsen's running of the University Computer Center—the open hours were not long enough and the help was not always available. Matsen replied to the President that if he were to look at the University books, that he would find that there was no computer center. In fact, Matsen had bought a computer with grant funds, and was allowing other faculty to sometimes use it, even to the extent of providing some help from his (Matsen's) graduate students. Matsen went on further to say, "But the University should have a computer center." The recommendation was taken to heart, and Matsen had a great influence on how the Texas Advanced Computer Center (and Department of Computer Sciences) developed. Doug further comments, “In particular, I think that UT was one of the first universities to view the computer as a resource like a library with access to be provided to all faculty, and ultimately all students. I think that his foresight in the general use of the computer in research and in education is a landmark idea and attitude.”
Doug has kindly provided a brief insider’s view of Matsen’s professional career. Doug writes, “Professor Matsen had several avenues of research interest. He championed the use of computers for scientific research, and was, in part, responsible for UT taking a leading role in this area. His particular computational research, almost entirely, was focused on the description of the electronic structure of atoms and molecules. Relevant schemes for integral evaluation were developed and turned into operative computer programs in his group. There was a very comprehensive table of molecular integrals published from his group, Quantum Chemistry Integrals and Tables. Seminal work was done on a series of small diatomic molecules (mostly of < 5 electrons), both in their ground states and excited states. Several renowned scientists working with computers came out of his group. Also, Professor Matsen’s interest in the use of the computer carried over to education so that (in the 1970s) he instituted some of the first “computeraided lectures”, and coursework.
Professor Matsen also was deeply interested in symmetry and the role of group theory in physics and chemistry. He developed a “spinfree quantum chemistry” both for making computations on the basis of the nonrelativistic (spinfree) Schrödinger equation for electronic structure and for the avoidance of misconceptions about the role of spin. This work started out with heavy consideration of the symmetric group of permutations (of particle indices), and the general theory of symmetry adaptation. In the early 1970s, Matsen switched more to the consideration of spinfree problems in terms of the unitary group (of spinfree orbital transformations). There was a long series of spinfree quantum chemistry papersmore than 30 in numberand the use of the unitary group was covered in a book coauthored with R. Pauncz. But Matsen’s grouptheoretic research also covered crystalfield and ligandfield theory for coordination complexes, as well as nuclearshell theory. Symmetry was also always prominent in the various graduate classes that Professor Matsen taught. Some appeared even in his freshman course on The Vector Space Theory of Matter, which was heavy with a simple linear algebraic presentation of quantum mechanics.
Professor Matsen was a decadeslong consultant for Exxon in Houston, where he addressed many practical problems,such as the conversion of coal to oil.”
Professor Matsen published over 200 scientific articles and was the author of three books. In 1979, he helped form the Institute for Theoretical Chemistry, which is made up of faculty from the Department of Chemistry and Biochemistry and the Department of Chemical Engineering. For over 40 years, he taught a freshmen chemistry course from the perspective of modern quantum mechanics called The Vector Space Theory of Matter. He teamed with Austin Gleeson to give one of the first team taught courses in the college. It was a course on light. Upon retirement, Matsen continued with his research and was appointed professor emeritus in 1997.
Dr. Matsen was married to Cecilia Kirkegaard Matsen who preceded him in death in January of 2006. They are survived by two children, Frederick Albert (Rick) and his spouse, Anna Lovell Matsen, and Megan Cecelia and her spouse, Albert Meisenbach. Additionally, they have three grandchildren, Susanna Lovell Matsen, Frederick Albert Matsen IV, and Laura Jane Megan Matsen.
Matsen Photo Album 


The following article can be found in its entire length in:
Int. J. Quantum Chem. 41, 714 (1992).
That shown here was from a scan done by Matsen and included on an excellent web site:
Early Ideas in the History of Quantum Chemistry
http://www.quantumchemistryhistory.com
Copyright © Feb. 23, 2002 by U. Anders, PhD
F. A. Matsen
Departments of Chemistry and Physics, The University of Texas, Austin, 78712
My introduction to quantum chemistry occurred as an undergraduate member of Farrington Daniel's research group at the University of Wisconsin in 1935. Albert Sherman, a postdoc member of the group, gave a series of informal lectures which provided a marvelous introduction to the subject. He had just finished writing (with J. H. Van Vleck) The Quantum Theory of Valence [Rev. Mod. Phys. 7, 167 (1935)]. The following quotation from this article made a lasting impression on me:
"Actually the only forces between spins are magnetic forces
which are exceedingly small, and the only reason that spin
figures in the answer is that the constraints imposed by the
Pauli principle correlate different spin alignments with different
electrostatic exchange energies.
Thus spin is only an indicator ... " (emphasis by FAM)
Al {Sherman, website note} had taken his degree with Henry Eyring at Princeton, so that it was only natural that I should do the same. The Princeton faculty in 1937 was very impressive with people like Einstein, Wigner, Weyl, Eyring, etc. Eyring was a very enthusiastic researcher bubbling over with new ideas. He gave a very good quantum mechanics course which later served as the basis for the Eyring, Walters, and Kimball's Quantum Chemistry (Wiley, New York, 1944).
There were many great seminars, among which I remember George Kimball's outstanding seminar entitled Group Theory of Directed Valence. Among my classmates were John Walters, Walter Kauzman, John Tukey (who became a famous mathematician), and Walter Moore (who has just published a biography of Schrödinger).
After a brief stint at Bucknell, I moved to Texas in 1942 where I have been ever since. My first research was on the theory of liquids, and my first quantum chemistry research was The Molecular Orbital Theory of the Spectra of Monosubstituted Benzenes [1]. I was helped by several summers at the University of Chicago where I interacted with Robert Mulliken, Clemens Roothaan, and John Platt. Robert was a gentle and committed man. I still remember his blackboard being completely covered, but he could always find space to make notations from his conversations. I don't know if the blackboard was ever erased. Clemens was in the process of formulating his famous LCAOSCF theory. John was active in the interpretation of electronic spectra.
Matsen in 1958
During that period, quantum chemists assembled at the Ohio State Spectroscopic Conference in Columbus, the precursor of the Sanibel Conference. It was there I met PerOlov Löwdin, Hertha Sponer, and many other quantum chemists.
My spectral theory [1] was good enough to impress Linus Pauling, who, as a member of the Guggenheim Committee, was responsible for my working with Charles Coulson at King's College London and Oxford in 1951. Coulson was very kind and always ready to listen. After listening, he would go to the board and summarize the idea to see if he understood it (he always did) and then contribute helpful suggestions and literature citations.
During this time, I met Michael Dewar, David Craig, lan Ross, Ron Brown, LonguetHiggins, LennardJones, and many others.
Michael Barnett was also with Coulson, at that time on leave from IBM. He sold me on machine computation during several teas at the Lyons' Corner House and even showed me how to program an exchange integral. After my return to Texas, Bob Hurst, Jimmy Miller, and 1, [3] with an IBM CPC (cardprogrammed computer) and a sixconfiguration valencebond function computed for lithium hydride a dipole moment of 6 debye.
I reported this to Peter Debye (then advisor to the Welch Foundation). He asked if the dipole moment of LiH could be measured. I replied in the negative since I knew it dissociated into Li + H2 on heating and into ions on solution. He then asked why I would want to calculate it if it couldn't be measured. Three years later, Klemperer obtained 5.9 debye with a molecularbeam, starkeffect spectrometer in which a small amount of LiH was formed. On reporting this to Debye, he asked why I would want to calculate it if it could be measured. Debye later made his attitude even clearer by stating that only people without ideas made calculations.
It is of interest in this connection that the 1956 Austin Quantum Chemistry Conference [2] passed a strong resolution proclaiming the importance of powerful computers for the development of quantum chemistry.
Next, in 1955, the University of Texas acquired an IBM 650 on which we made many calculations, summarized in a review article with J. C. Browne [4]. Miller, Gerhauser, and Matsen's Quantum Chemistry Integrals and Tables [5] were computed on this 650. PerOlov has a number of funny stories about the tables, the Russians, and the CIA.
The University of Texas has continued to expand its computing facilities, until it now has a Center for HighPerformance Computing which houses two Universityowned Cray supercomputers. In 1986, Jim Browne, Bob Wyatt, T. Tajima, and I organized a conference entitled Algorithms, Architectures and Scientific Computing [6]. Jim Browne now does exclusively computer science, T. Fujima models hightemperature plasmas, and Bob Wyatt, currently director of our Theoretical Chemistry Institute, does highlevel computing on molecular dynamics and neural networks.
My first publication in algebraic quantum chemistry appeared in the proceedings of the Austin Conference [2]. This research began with my noticing in class that the calculation of eigenvectors of S2 was just like the symmetry adaptation in molecular vibration theory. This suggested group theory, and I identified the group as the symmetric group (30 years after Wigner).
It was at this time that I proposed spinfree quantum chemistry based on the symmetric group, which employs only freeon (spinfree) orbitals and where the Pauli principle is imposed by restricting the physical freeon spaces to those labeled by partitions of the form [Lambda] = [2N/2S ,1S ], where S is the spin quantum number.
Matsen in 1961
I remember worrying, during a walk, about the connection between spinfree quantum chemistry and valencebond theory. It seemed to me that since there were five singlet Rumer structures for benzene the dimension of the [Lambda] = [23]th irreducible representation should also be five. I verified this on my return home and felt that the spinfree formulation was essentially correct.
My motivation for formulating spinfree chemistry was to separate the spin kinematics (only an indicator) from the freeon dynamics which contains the basic physics, i.e., the spinfree Coulomb repulsion. It has some pedagogical value in reducing the possible misinterpretation of statements like "electrons with parallel spins repel and electrons with antiparallel (paired) spins attract."
We went on to publish 25 papers on spinfree quantum chemistry [7]. The formal algebra was summarized in an article entitled "Frobenius Algebra and the Symmetric Group" [8]. In this development, I was greatly aided by an NSF Senior PostDoctoral Fellowship at the Institut Henri Poincaré in 1961. The highlight of the year was the communication of my paper entitled "SousAlgebre de Complexes Assocoiés en Spectroscopie Theorique" [9] to the French Academy by Nobel Laureate, M. deBroglie.
While in Paris, I interacted with the Pullmans, the Daudels, Roland Lefebvre, Carl Moser, and Bob Nesbit.
The idea of spinfree quantum chemistry was not widely accepted by the chemical community because everyone knows that an electron carries spin. To obtain wider acceptance, I wrote "Chemistry without Spin" for the Journal ot the American Chemical Society [10]. This was sent sequentially to three pairs of reviewers, each pair reporting that the paper was wrong or trivial. Finally, Bob Parr (the theoretical chemistry editor) overruled the divided reviewers and the paper was published. Let it be recorded that this paper had no effect whatever.
There are at least three reasons for the lack of acceptance of spinfree quantum chemistry:
(i) Antisymmetrization (or the Slater determinant) is easy to learn and to program on a computer.
(ii) Spin arrows are vivid and require no mathematics.
(iii) Spinfree quantum chemistry requires some knowledge of group theory. I offer as my only defense witness Hermann Weyl who wrote in the preface of his 1930 edition of The Theory of Groups and Quantum Mechanics as follows:
"It is rumoured that the group pest is gradually being
cut out of quantum physics... and as far as the permutation
group, it does seem indeed possible to avoid it with the aid
of the Pauli exclusion principle. Nevertheless, the theory
must retain the representations of the permutation group as
a natural tool to obtain an understanding of the relationships
due to the introduction of spin so long as its specific dynamic
effect is neglected."
My next adventure in algebraic quantum chemistry began in 1973 when Marcos Moshinsky invited Doug Klein and me to Mexico City. Doug, who had just returned from working with Zoos at Princeton, lectured to us on the Hubbard Hamiltonian. Marcos then showed that the Hubbard Hamiltonian could be expressed as a seconddegree polynomial in the generators of the unitary group with the generators expressed as products of secondquantized operators.
This led me to develop a spinfree, unitarygroup formulation of quantum chemistry in which the physical irreducible spaces of the unitary group were labeled in the same way as for the spinfree symmetric group formulation. In this case, the algebraic quantum chemistry is based on the Lie algebra of the unitary group rather than on the Frobenius algebra of the symmetric group. This idea had been anticipated by Weyl and later by Patterson and Harter. I presented this research at the 1973 Sanibel Symposium [II].
The application of the unitary group to quantum chemistry was skillfully exploited by Paldus and Shavitt in the GUGA (graphical unitary group approach) method. The method is quite well adapted to largescale computation and has been profitably applied by Schaefer and others.
The rapid development of the subject was exhibited by the wellattended Unitary Group Workshop at Bielfeld, hosted by Jürgen Hinze in 1979 (proceedings published by SpringerVerlag), to which I contributed a paper [12].
Next, I applied the spinfree, unitarygrouptheory to the theory of organic chemistry in 1975. Here, I used the HückelHubbard Hamiltonian with a single correlation parameter
0 < x = U/(U + t) < I,
where U is the repulsive energy of two electrons on a single site and where t (the negative of the Huckel [13] is the hopping integral.
This theory was first presented in a lecture series at Hafia [13] under the sponsorship of Ruben Pauncz. Ruben and I later collaborated on the monograph entitled Unitary Group and Quantum Chemistry [14].
I have enjoyed a number of other profitable residences for which I am extremely grateful: Uppsala with PerOlov Löwdin, Yngve Ohm, JeanLouis Calais, Erkki Bråandas and Osvaldo Goscinski; Waterloo with Jiří Čížek and Joe Paldus; Nijmegen with Paul Wormer and Ad van der Avoird; Madison with Joe Hirschfelder and John Harriman; Salt Lake City with Joseph Michi, Jack Simons, and Frank Harris; Graz with Harold Fritzer; and Aarhus with Jan Linderberg and Poul Jorgensen.
I recently {1990, website note} summarized several connections established by the HückelHubbard Hamiltonian [15]:
(i) molecular orbital and valencebond theory;
(ii) the exchange approximation and full Ci;
(iii) conductors, semiconductors, and insulators; and
(iv) normal and superconductors.
This was my contribution to the PariserParrPople paper symposium. On this occasion, Bob Parr pointed out that the Hubbard approximation to the PPP Hamiltonian was first proposed by the quantum chemists, LonguetHiggins and Salem [J.Chem. Phys. 34, 1914 (1961)] 2 years before Hubbard  the solidstate physicist.
....
....
....
Recently {1990, website note} I have applied the freeon concept to nuclei and elementary particles.Here, again, the fermion orbitals are factored into freeon orbitals and energetically inert orbitals (ordinary spin orbitals for electrons, isospin orbitals for nuclei, and ordinary spin times color orbitals for quarks). This extension was the subject of my Löwdin Lecture at the University of Uppsala [17].
A scientifically (and financially) rewarding part of my career has been the 40 years I spent as a consultant to the Exxon Corporation both in Texas and New Jersey. In the early years, a great deal of basic research was carried out in Texas.
I particularly remember my interactions with Joe Franklin (later at Rice University) and Frank Field (later at Rockefellow University) who became the established authorities in ionmolecule reactions carried out in a highpressure mass spectrometer.
My greatest Exxon adventure was my participation in the design of a coalliquefaction unit to reduce our country's dependence on petroleum. In this research, I made considerable application of my knowledge of theoretical organic chemistry; Lonnie Vernon and I used pure compounds to establish the basic mechanism for the liquefaction. The semiplant performed above specifications, but the project was shut down because of the precipitous drop in oil prices in the early 1980s. Perhaps the current {1990, website note} Middle East crises will bring it out of mothballs.
Amusingly, I had been lecturing at an unnamed university on the unitary group formulation of the manybody theory. I apparently went way over the listeners' heads since the only question I got was,
"What possible use could you be to Exxon? "
Finally, I wish to comment briefly on the teaching of quantum mechanics. Because quantum mechanics is unlike anything the beginning student has seen before, because quantum mechanics challenges the conventional concepts (truth, reality, meaning), and because considerable abstract mathematics is required, quantum mechanics poses a serious intellectual challenge to the student. Bob Wyatt and I have had considerable success, at both the undergraduate and graduate levels, at the University of Texas with the following:
(i) Begin early before their minds have been contaminated.
(ii) Emphasize the pragmatic value judgements of a theory: diversity, accuracy, and simplicity (Ockham's razor), and point out that the idealistic value judgements of truth, reality, and meaning are both unnecessary and counterproductive for the progress of science.
(iii) Teach the science and the mathematics simultaneously. Then, science provides the motivation for the study of abstract mathematics and the mathematics provides a realization of the science.
Selected Bibliography
[1] Molecular orbital theory and the spectra of monosubstituted benzenes. J. Amer. Chem. Soc. 72, 5243 (1950).
Annual Rev. Phys. Chem. 1, 133150 (1950).
[2] Texas J. Sci. 8, 194 (1956).
[3] with R. P. Hurst and J. Miller, The dipole moment of lithium hydride. J. Chem. Phys. 26, 1092 (1957).
[4] with J. C. Browne, Ab initio calculations on small molecules. Adv. Chem. Phys. 23, 1961 (1973).
[5] with J. Miller and J. M. Gerhauser, Quantum Chemistry Integrals and Tables. (The University of Texas Press, 1959).
[6] with T. Tajima, Algorithms, Architectures and Scientific Computation (The University of Texas Press, 1986).
[7] SpinFree Quantum Chemistry :
I. Introduction, in Advances in Quantum Chemistry, P.O. Löwdin, Ed. (Academic Press, New York, 1963.
II. Threeelectron systems. J. Phys. Chem. 68, 3282 (1964).
III. Bond functions and the Pauling rules (with A. A. Cantu and R, D. Poshuta). J. Phys. Chem. 70, 1558 (1966).
IV. The p" electron configuration. J. Phys. Chem. 70, 1568 (1966).
V. Spin density (with A. A. Cantu). J. Phys. Chem. 72, 21 (1968).
VI. Spin conservation (with D. J. Klein). J. Phys. Chem. 73, 2477 (1969).
VII. Spin conservation (with A. A. Cantu). J. Phys. Chem. 73, 2488 (1969).
VIII. The Slater derminant (with M. L. Ellzey). J. Phys. Chem. 73, 2495 (1969).
VIX. The aggregate theory of polyelectronic systems (with D.J. Klein). J. Phys. Chem. 75, 1860 (1971).
X. Effective spin Hamiltonians (with D.J. Klein). J. Phys. Chem. 76, 235 (1972).
XI. Perturbation Theory for interaction energies (with B. R. Junker). Int. J. Quantum Chem. 6,411 (1972).
XII. Coarse structure magnetic theory (with A. L. Ford). Int. J. Quantum Chem. 7, 1051 (1973).
XIII. Spin waves (with J.E. Suger and J.M. Picone). Int. J. Quantum Chem. 7, 1063(1973).
XIV. The infinite interaction range model for ferromagnetism (with J.G. Cosgrove and J.M. Picone). Int. J. Quantum Chem. 7, 1077 (1973).
XV. Spinonly neutron diffraction (with J. M. Picone and T. L. Welsher). Int. J. Quantum Chem. 9,157 (1975).
XVI. Spin correlation (with T.L. Welsher). Int. J. Quantum Chem. 9, 171 (1975).
XVII. The WoodwardHoffman Rules. Int. J. Quantum Chem. 10, 511 (1976).
XIX. Particlehole and pairing symmetries (with T.L. Welsher and B. Yurke). Int. J. Quantum Chem. 12, 985 (1977).
XX. The alternacy quantum number (with T. L. Welsher and B. Yurke). Int. J. Quantum Chem. 12,1001 (1977).
XXI. Hartree Fock theory (with C.J. Nelin). Int. J. Quantum Chem. 15, 751 (1979).
XXII. Multiconfiguration selfconsistent field theory (with C. J. Nelin). Int. J. Quantum Chem. 20,861 (1981).
XXIII. The generatorstate approach. Int. J. Quantum Chem. 32, 71 (1987).
XXIV. Freeon manybody theory. Int. J. Quantum Chem. 32, 87 (1987).
XXV. The unitarygroup formulation of Fermion manybody theory. Int. J. Quantum Chem. 32,105 (1987).
[8] Frobenius algebra and the symmetric group, in Group Theory and Applications, Vol. 3 (1975),p. 131. See also Vector Spaces and Algebras for Chemists and Physicists (HoltRinehart, New York, 1970).
[9] Sousalgebre de complexes en spectroscopie théorique. Comp Rendus 254, 2298 (1962).
[10] Chemistry without spin. J. Am. Chem. Soc. 92, 3525 (1970).
[11] The unitary group formulation of the N particle problem. Int. J. Quant. Chem. 8S, 379 (1974).
[12] Lecture Notes in Chemistry, The Unitary Group, Vol. 22 (SpringerVerlag, New York, 1979), p. 345.
[13] Quantum organic chemistry and the unitary group. Isr. J. Chem. 19, 201 (1980).
[14] with R. Pauncz, The Unitary Group in Quantum Chemistry, (Elsevier, New York, 1986).
[15] The Hubbard connection. Int. J. Quantum Chem. 37, 389402 (1990).
[16] Physical Chemistry of high temperature superconductivity. 2, 118 (1988), American Chemical Society Publication.
[17] Freeon unitary group procedure and the structure of matter. Int. J. Quantum Chem. Quantum Chem. Symp. 21, 713728 (1987); The unitary group and the structure of matter, in Annales, (Academiae Regiae Scientiarum Upsaliensis, Kungi. Vetenskapssamhällets, i Uppsala Årsbok, 198788), Vol. 27.
Further annotations to F.A. Matsen's biography :
Consultant to the Exxon Corporation for 40 years.
Awards/Honors:
Guggenheim Fellow
NSF Senior Postdoctoral Fellow
American Physical Society Fellow
Löwdin Distinguished Lecturer, Uppsala University Sweden
Fellow, International Academy of Quantum Molecular Science Establishment of the annual F.A. Matsen Regental Lectures on the Theories of Matter
Professional Societies:
American Chemical Society
American Physical Society,
American Association for the Advancement of Science
Sigma Xi, Sigma Pi Sigma
Editorial Boards:
Journal of the American Chemical Society
International Journal of Quantum Chemistry
Advances in Quantum Chemistry