Photochemistry and Spectroscopy Department

Institute of Physical Chemistry, Polish Academy of Sciences



For porphycenes isolated in supersonic jets or helium nanodroplets, tunneling splittings are observed due to quantum delocalization of two inner protons. The values of the splittings are vibrational-mode-selective.


In condensed phases, trans-trans tautomerization occurs in femtoseconds/picoseconds, depending on the peripheral substitution pattern.


The trans form is dominant, but the rare cis1 form has also been detected. The cis2 tautomer is postulated to be a crucial structure in the process of radiationless depopulation of the lowest excited singlet state.


The main path of tautomerization in porphycene is a self-exchange process, i.e., the substrate and product are chemically identical. We have developed  methodologies for the determination of ground and excited state tautomerization rates for such a particular case of a chemical reaction.