In collaboration with the Femtosecond Group (www.femtolab.au.dk), photochemical reactions in the picosecond region are studied. This type of experiments is characterized by the absence of reactions among the photo-products which facilitates investigations of the primary photochemical reactions. The contribution of computational chemistry is to provide theoretical predictions of the properties of potential photo-products using techniques of computational chemistry, typically on clusters containing the photo-product and a number of solvent molecules.
Jan Thøgersen, Ane Gadegaard, Jakob Nielsen, Svend Knak Jensen, Christian Petersen, Søren R. Keiding, "The primary formation dynamics of peroxynitrite following photolysis of nitrate", J. Phys. Chem. A. 113, 10488, 2009. Svend Knak Jensen, Søren Rud Keiding, Jan Thøgersen, "The hunt for CHO(aq)", Phys. Chem. Chem. Phys., 12, 8926-8933, 2010.
In collaboration with the interdisciplinary Mars Simulation Laboratory (www.marslab.dk), laboratory analogs of chemical reactions on planetary bodies are studied. The main interest is to study chemical reactions mediated by the wind action. This is simulated by placing a selected chemical in a closed container in a well defined environment (i.e., chemical composition of the atmosphere, at various pressures and temperatures) and exposing the container to gentle mechanical agitation. In a recent investigation the technique has demonstrated that magnetite can be oxidized to hematite after several months of gentle agitation. This finding offers a mechanism -not involving atmospheric water and oxygen- for the reddish color of Mars. Current research in this area is focused on finding simple mechanisms that can explain the observed oxidative state of the Martian surface.
Jonathan Merrison, Haraldur P. Gunnlaugsson, Per Nørnberg, Svend J. Knak Jensen, "Mineral alteration induced by sand transport; a source for the reddish color of Mars", Icarus, 205(2), 716-718, 2010.
An ongoing collaboration exists with groups in Canada and Hungary, studying reaction mechanisms and properties of the folding process of peptides using electron structure calculations and statistical mechanical techniques.
Alice Maetzke, Svend J. Knak Jensen, Imre G. Csizmadia, "Putative mechanisms of peroxybicarbonate formation", Chem. Phys. Lett. 448, 46-48, 2007. Bela Viskolcz, Imre G. Csizmadia, Svend J. Knak Jensen, Andras Perczel, "Polymerization dependence of the entropy of homo-oligomer peptides", Chem. Phys. Lett. 501, 30-32, 2010.