Clemens C. J. Roothaan

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Clemens C. J. Roothaan (August 29, 1918 – June 17, 2019) was a Dutch physicist and chemist known for his development of the self-consistent field theory of molecular structure.

Biography

Roothaan was born in

concentration camp for involvement with the Dutch Resistance. On September 5, 1944, the remaining prisoners of the camp (including the Roothaan brothers) were moved to the Sachsenhausen camp in Germany ahead of the advancing Allies. Near the end of the war, the Sachsenhausen inmates were sent on a death march which Roothaan's brother did not survive.[2]

While a prisoner of war he was able to pursue his studies in physics together with other professors and students under the formal guidance of

The Catholic University of America in Washington, D.C.. He realised that the then current approach to molecular orbital theory was incorrect and changed his topic to what resulted in the development of the Roothaan equations. Prof. Mulliken mentions this work in his Nobel lecture[3]
as follows:

I tried to induce Roothaan to do his Ph.D. thesis on Hückel-type calculations on substituted benzenes. But after carrying out some very good calculations on these he revolted against the Hückel method, threw his excellent calculations out the window, and for his thesis developed entirely independently his now well known all-electron LCAO SCF self-consistent-field method for the calculation of atomic and molecular wave functions, now appropriately referred to, I believe, as the Hartree-Fock-Roothaan method.[4]

— Robert S. Mulliken

He had moved to the University of Chicago in 1949 and his PhD was awarded in 1950. He then joined the Physics Department of the University of Chicago. From 1962 to 1968 he was Director of the University of Chicago Computation Center. Later he was Professor of Physics and Chemistry at the University of Chicago. Since his retirement, in 1988, he has worked for the Hewlett-Packard Laboratories in Palo Alto, California, where his primary contribution has been in the development of the mathematical coprocessor routines for the Itanium chip. His method of analyzing pipeline architecture has been unique and innovative and greatly admired in supercomputer circles around the world.

In 1982 Roothaan became a correspondent of the Royal Netherlands Academy of Arts and Sciences.[5] He was a member of the International Academy of Quantum Molecular Science and the Society of Catholic Scientists.[6] He turned 100 in August 2018[7] and died in June 2019.[8]

Works

Autobiographies

  • Roothaan, Clemens C. J. (1991). "My life as a physicist: Memories and perspectives". Journal of Molecular Structure: THEOCHEM. 234: 1–12.
    doi:10.1016/0166-1280(91)89002-I
    .
  • Roothaan, Clemens C. J. (1993). "My life as a physicist: Memories and perspectives". International Journal of Quantum Chemistry. 48 (S27): 1–11.
    doi:10.1002/qua.560480804
    .

See also

References

  1. ^ "Clemens C. J. Roothaan". International Academy of Quantum Molecular Science. Retrieved 7 August 2013.
  2. ISBN 978-0-262-01618-6
    .
  3. PMID 5338306
    .
  4. doi:10.1103/RevModPhys.23.69
    .
  5. ^ "Clemens Roothaan". Royal Netherlands Academy of Arts and Sciences. Archived from the original on 30 August 2018. Retrieved 4 August 2015.
  6. ^ "Society of Catholic Scientists". www.catholicscientists.org. Archived from the original on 2018-09-13. Retrieved 2018-09-13.
  7. ^ @FrancescIllas (August 29, 2018). "Clemens Roothaan is 100 years old today. A big name in Quantum Chemistry!" (Tweet). Retrieved 2018-10-17 – via Twitter.
  8. ^ "News & Announcements". www.qtp.ufl.edu. 19 June 2019. Retrieved 22 June 2019. Clemens C.J. Roothaan died June 17th

External links

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