Inga Fischer-Hjalmars


Born January 16, 1918 in Stockholm, Sweden. Emeritus Professor of Theoretical Physics at the University of Stockholm, Sweden.

Member of the Royal Swedish Academy of Sciences (1978); Foreign Member of the Royal Danish Academy of Sciences and Letters (1982); Member of the International Academy of Quantum Molecular Science (1983); International Society of Quantum Biology Award (1985); New York Academy of Sciences; Human Rights of Scientists Award (1990).

Author of:

Approximately 100 papers, on experimental physical chemistry of molecules, on quantum chemistry and on solid state theory.

Important Contributions:

A comparison was made together with Coulson of Molecular orbital (MO) and valence bond (VB) methods in their simplest as well as more advanced forms with application to the hydrogen molecule. It was shown that the two methods are different approximations of the same more general method of configuration interaction type.

In search for a parameter for classification of different semiempirical versions of the MO method, the matrix elements were expanded with respect to the overlap integral S between nearest neighbours. The principal result was that the Hückel method is correct to the first order of S, and the Pariser-Parr-Pople (PPP) method to the second order of S. With coworkers this result was used for developing a modified parameter scheme of the PPP type, first applied to organic molecules and later extended to transition metal complexes with applications, e.g. to porphyrins.

Employing ab initio methods of medium accuracy, model complexes of metals in biology (Mg, Fe, Cu, Zn, etc.) are investigated. Studies with coworkers have been made of the binding of the metal ion to heteroatoms of unsaturated organic molecules, including both hard and soft ligands, electron affinities of the complexes, charge distributions, oxidation state of the metal, lowlying excited states of the complex, the transfer of electron density between metals and ligands as models of biological oxidation-reduction processes, etc.

In the theory of condensed matter, contributions have been made to comparisons between discrete and continuum models of media with polar micro-structure, such as molecular crystals and composite materials, for the description of elastic properties, e.g. dispersion of sound waves.

An obituary can be found at IngaFish-Hjalmar.pdf.