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University of Helsinki
 
Solid State Spectroscopy and Photochemistry Research Group
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Contact address:
 Laboratory of Physical Chemistry,
Department of Chemistry,
University of Helsinki
P.O. BOX 55 (A.I.Virtasen aukio 1),
FIN-00014 University of Helsinki, Finland

Fax: +358-9-19150279


7th ICLTC organized in Helsinki in August 2008

The 7th international conference of low temperature chemistry (7th ICLTC) is organized by the research group. The conference will take place during 24-29 of August 2008 close to Helsinki downtown, in culture centre Sofia in Kallvik.

The conference provide a convenient meeting place for students, researchers and experts interested in the chemistry taking place in cold condition close to the zero temperature. The conference topics will include dynamics in low temperatures, chemistry and physics in cryosolids, quantum solids, ices and their role in atmospheric chemistry, cold beams and clusters and challenges for theory and computations.

The conference www-pages can be found at http://www.helsinki.fi/kemia/ICLTC-2008

Our formic acid studies makes it into the PCCP cover
 A recent report on formic acid isomerization reaction in solid p-H2 made it to the Phys.Chem.Chem.Phys. cover in November 2007. The paper and the cover can be accessed from the PCCP web-site.

High-energy conformer of formic acid in solid hydrogen: conformational change promoted by host excitation

Kseniya Marushkevich, Leonid Khriachtchev and Markku Räsänen
Phys. Chem. Chem. Phys. 9 (2007) 5748-5751.

Abstract:
Conformers of formic acid (FA) are studied by IR spectroscopy in solid hydrogen. The higher-energy cis -FA conformer is prepared by vibrational excitation of the ground-state trans -FA conformer. The quantum yield of the trans to cis conformational process in solid hydrogen appears about two orders of magnitude smaller than in solid argon, which is explained by efficient coupling of the vibrationally excited trans form with the host vibrations deactivating the conformational change. The trans to cis conformational process is efficiently promoted by excitation of the hydrogen-matrix rovibrational transitions (host excitation), which confirms the strong coupling between vibrations of the host and embedded molecule. These results demonstrate a unique process of conformational reorganization mediated by vibrational excitation of the host. The tunneling decay of the cis -FA monomer in solid hydrogen is found to be 4 times faster than in solid argon but 30 times slower than in solid neon, and this is discussed in terms of the matrix solvation effect.