A Snapshot of Molecular Electronic Structure Theory and Its Applications

Erkki Brändas was born in Tampere, Finland in July1940 and was, as a Finnish war child, transported to Sweden in February 1942, finally adopted by his Swedish parents and given Swedish citizenship in 1947. He received his FL (PhD) in 1969 and Doctor of Philosophy (habilitation) in 1972, both at Uppsala University. Except for guest professorships in USA, Germany, Israel, he spent his professional career in Uppsala employed as Assistant- Associate- and Full Professor from 1975 until retirement in 2007. In addition to serving as chairman of the department of Quantum Chemistry, he was appointed Executive Director of the Uppsala Graduate School Advanced Instrumentation and Measurement supervising the doctoral education of 35 PhD’s from 1997-2007. He has served on various international scientific and editorial boards, e.g. Wiley, Elsevier and Springer including the service as Editor-in-Chief for the International Journal of Quantum Chemistry, Series Editor of the Advances in Quantum Chemistry. He is the current President of the International Society for Theoretical Chemical Physics, since 15 years, chairing a variety of international congresses and other numerous meetings, schools and workshops. He has published over 260 articles and edited more than 50 books on fundamental theoretical chemical physics from research on atoms, molecules and solid-state physics to complex enough systems in biology – from the microscopic realm to the cosmological rank.

Rod Bartlett pioneered the development of coupled-cluster (CC) theory in quantum chemistry to offer highly accurate solutions of the Schroedinger equation for molecular structure and spectra, presenting the CCSD, CCSD[T], CCSDT, CCSDT[Qf], and CCSDTQ methods among many others. He extended the CC theory to excited, ionized, and electron attached states with his equation-of-motion EOM-CC methods. His group formulated analytical gradient theory for CC theory, making it possible to readily search potential energy surfaces and to provide vibrational spectra. His group introduced the STEOM-CC extensions for excited states.

His group is also responsible for the widely used ACES II and massively parallel ACES III program system. He is the author of more than 500 journal articles and book chapters. He is the co-author with Isaiah Shavitt of the definitive book on coupled-cluster theory, “Many-Body Methods in Chemistry and Physics: MBPT and Coupled-Cluster theory,” Cambridge Press, 2009.

Born in Aberystwyth, Wales and educated at Trinity College Cambridge, Philip Hoggan has always been French and British. After a mathematical chemistry background, he has studied a number of theoretical systems, with a DSc by research obtained in 1991 at Nancy, France on the way physical interaction between molecules and solid surfaces is a precursor to catalysis. This was treated entirely on the basis of Quantum Mechanics and applied, first to cis-trans butadiene isomerization on alumina and then a number of ‘organic’ reactions.
The first lectureship was at Caen, Normandy from 1992. This period led to some fundamental research of ab initio Slater electronic structure calculations for more than 3 atoms. The first related code STOP was published in February 1996 after much work by a postdoctoral fellow A. Bouferguène, now Professor at U Alberta. After continuing to study catalytic systems at Caen, from a theoretical viewpoint, Philip Hoggan was appointed to the Chair of Theoretical Chemistry in Clermont from May 1998. This is still essentially his teaching position, although research interests have switched to solid-state (surface) physics joining the Pascal Institute for physics in Clermont from 2005. This followed a visiting professor stay of 18 months at Tallahassee, Florida in Theoretical Physics.
Research emphasis has shifted from the STOP era (where the problem was solved by Coulomb Resolution in 2008) to Quantum Monte Carlo (QMC). The CNRS paid leave for a couple of years for Philip Hoggan to learn about this technique from Cyrus Umrigar, Julien Toulouse, Michel Caffarel and others. Of course, it eventually led to a project to calculate catalytic reactions on metal surfaces that was initiated by G-J Kroes (Leiden, NL) and his ERC in 2014. K Doblhoff-Dier arrived in Clermont for a ground-breaking research fellowship and each of us continues to produce very accurate work e.g. on hydrogen (production and dissociation on metals), as a clean fuel for renewable energy.
Now, in 2023 we enter the 400th anniversary of Blaise Pascal’s birth. He invented calculators, some of which are in the Clermont museum. It is wonderful to work in the institute that bears his name conducting QMC on catalytic hydrogen synthesis on super-calculators: the tools that trace their roots to his ‘Pascaline’.
Philip Hoggan is married and has twin daughters.