Theoretical chemists

Linus Carl Pauling ( PAW-ling; February 28, 1901 – August 19, 1994) was an American chemist, biochemist, chemical engineer, peace activist, author, and educator. He published more than 1,200 papers and books, of which about 850 dealt with scientific topics. New Scientist called him one of the 20 greatest scientists of all time. For his scientific work, Pauling was awarded the Nobel Prize in Chemistry in 1954. For his peace activism, he was awarded the Nobel Peace Prize in 1962. He is one of five people to have won more than one Nobel Prize (the others being Marie Curie, John Bardeen, Frederick Sanger, and Karl Barry Sharpless). Of these, he is the only person to have been awarded two unshared Nobel Prizes, and one of two people to be awarded Nobel Prizes in different fields, the other being Marie Curie.Pauling was one of the founders of the fields of quantum chemistry and molecular biology. His contributions to the theory of the chemical bond include the concept of orbital hybridisation and the first accurate scale of electronegativities of the elements. Pauling also worked on the structures of biological molecules, and showed the importance of the alpha helix and beta sheet in protein secondary structure. Pauling's approach combined methods and results from X-ray crystallography, molecular model building, and quantum chemistry. His discoveries inspired the work of Rosalind Franklin, James Watson, Francis Crick, and Maurice Wilkins on the structure of DNA, which in turn made it possible for geneticists to crack the DNA code of all organisms.In his later years, he promoted nuclear disarmament, as well as orthomolecular medicine, megavitamin therapy, and dietary supplements, especially ascorbic acid (commonly known as Vitamin C). None of his ideas concerning the medical usefulness of large doses of vitamins have gained much acceptance in the mainstream scientific community. He was married to the American human rights activist Ava Helen Pauling.

Raymond Daudel (2 February 1920 – 20 June 2006) was a French theoretical and quantum chemist.
Trained as a physicist, he was an assistant to Irène Joliot-Curie at the Radium Institute. Daudel spent almost the entirety of his career as professor at the Sorbonne and director of a laboratory of the Centre National de la Recherche Scientifique (CNRS). He is quoted as saying that the latter "was much better because the CNRS was very rich". This allowed Daudel to attract many co-workers from elsewhere in France and internationally.
Raymond Daudel was Officier de la Légion d'honneur and Officier de l'Ordre National du Mérite. He served as President of the European Academy of Arts Sciences and Humanities, in Paris, France. Daudel was a founding member and Honorary President of the International Academy of Quantum Molecular Science.An author as well as an academic, Raymond Daudel authored several books, including Quantum chemistry, originally with R. Lefebyre and C. Moser in 1959 (Interscience Publishers, Inc., New York) and later with G. Leroy, D. Peeters, and M. Sana, published by Wiley in 1983. He was responsible for the organization of the first International Congress in Quantum Chemistry, held in Menton, France in 1973.

Erich Armand Arthur Joseph Hückel (August 9, 1896, Berlin – February 16, 1980, Marburg) was a German physicist and physical chemist. He is known for two major contributions:

The Debye–Hückel theory of electrolytic solutions
The Hückel method of approximate molecular orbital (MO) calculations on π electron systems.Hückel was born in the Charlottenburg suburb of Berlin. He studied physics and mathematics from 1914 to 1921 at the University of Göttingen.
On receiving his doctorate, he became an assistant at Göttingen, but soon became an assistant to Peter Debye at Zürich. It was there that he and Debye developed their theory (the Debye–Hückel theory, in 1923) of electrolytic solutions, elucidating the behavior of strong electrolytes by considering interionic forces, in order to account for their electrical conductivity and their thermodynamic activity coefficients.After spending 1928 and 1929 in England and Denmark, working briefly with Niels Bohr, Hückel joined the faculty of the Technische Hochschule in Stuttgart. In 1935, he moved to Phillips University in Marburg, where he finally was named Full Professor a year before his retirement 1961. He was a member of the International Academy of Quantum Molecular Science.