matrix

Matrix isolation spectroscopy of small molecules

Characterization and dynamics of reactive species
Experiments using EPR, UV/VIS and IR spectroscopy based methods
Theoretical approaches include ab initio calculations (CC, MCSCF and MRCI),
classical molecular dynamics and combined quantum/classical methods

Research

In matrix isolation technique reactive atoms or molecules are trapped in chemically inert low temperature solid (T ~ 10 – 25 K) and studied by spectroscopic methods. This method can be used, for example, to study reaction intermediates or to probe for chromophore - matrix dynamics. In the former case our current interests are mainly in understanding various surface catalytic reactions. An example of such reaction is reduction of NO_x by hydrocarbons and Ag/alumina catalyst. Rigorous description of molecule - matrix dynamics poses a serious theoretical challenge since the quantum mechanical system typically consists of thousands of degrees of freedom. The main areas of interest are in applying diatomics-in-molecules (DIM) and semi-classical surface hopping methods to study charge separation and charge mobility in solid Kr and Xe.

Collaboration

Matrix isolation laboratory, Prof. H. Kunttu (University of Jyväskylä)
Technical chemistry laboratory, Prof. D. Murzin (Åbo Akademi University)

Representative publications

T. Kiljunen, J. Eloranta, and H. Kunttu, Ab initio and molecular dynamics studies on rare gas hydrides: potential energy curves, isotropic hyperfine properties, and matrix cage trapping of atomic hydrogen, Journal of Chemical Physics 110, 11814 (1999).

T. Kiljunen, J. Eloranta, H. Kunttu, M. Pettersson, L. Khriachtchev, and M. Räsänen, Electronic-structure and short-range recombination dynamics of S₂ in solid argon, Journal of Chemical Physics 112, 7475 (2000).

S. Fiedler, K. Vaskonen, J. Ahokas, H. Kunttu, J. Eloranta, and V. A. Apkarian, Host-guest charge transfer states: CN doped Kr and Xe, Journal of Chemical Physics 117, 8867 (2002).

T. Kiljunen, J. Eloranta, J. Ahokas, and H. Kunttu, Magnetic properties of atomic boron in rare gas matrices. An electron paramagnetic resonance study with ab initio and diatomics-in-molecules molecular dynamics analysis, Journal of Chemical Physics 114, 7144 (2001).

K. Arve, E.A. Popov, M. Rönnholm, F. Klingstedt, J. Eloranta, K. Eränen, D. Yu. Murzin, From a fixed bed Ag-alumina catalyst to a modified reactor design: how to enhance the crucial heterogeneous-homogeneous reactions in HC-SCR?, Chemical Engineering Science 59, 5277 (2004).

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