2013 Aminoff Prize

Carlo Gatti

Mark Spackman

The Royal Swedish Academy of Sciences (RSAS) has awarded the Gregori Aminoff Prize in Crystallography 2013 to Carlo Gatti (Inst. of Molecular Sciences and Technology, Italian National Research Council (CNR-ISTM), Milan, Italy) and Mark Spackman (U. of Western Australia, Crawley, Australia), 'for developing experimental and theoretical methods to study electron density in crystals, and using them to determine molecular and crystalline properties'. SEK 100,000 to be shared equally between the Laureates.

Both Carlo Gatti and Mark Spackman have independently developed concepts for interpreting electron-density distributions related to quantum chemistry theory, using multipole analysis of high-quality X-ray diffraction data. This approach has, in particular, significantly demonstrated and quantified the role of hydrogen bonding in molecular systems. 'Charge density topology' is important for classification of the type and strength of chemical bonding in solid compounds and molecules. The Prize will be awarded at the Royal Swedish Academy of Sciences' Annual Meeting on April 5, 2013.

One key concept developed by Carlo Gatti is the source function (Bader & Gatti, 1998), which permits visualization of chemical bonds and other fundamental chemical properties using only information from observed electron density and its derivatives. The function equates values of observed density at any point within the crystal to a sum of atomic contributions. Mark Spackman devised and implemented a new scheme for partitioning crystal space into molecular and atomic volumes limited by Hirshfeld surfaces, which reflect the nature and strength of interatomic and intermolecular interactions in quantitative terms. An exploratory paper (Spackman & Byrom, 1997), focusing on electron distributions derived from X-ray diffraction data on urea, clearly demonstrated the significance of Hirshfeld surface analysis.