dc.creator Zheldakov, I. L. en_US dc.creator Mereshchenko, A. S. en_US dc.creator Tarnovsky, A. N. en_US dc.date.accessioned 2010-07-12T14:01:05Z dc.date.available 2010-07-12T14:01:05Z dc.date.issued 2010 en_US dc.identifier 2010-FE-02 en_US dc.identifier.uri http://hdl.handle.net/1811/46157 dc.description Author Institution: Bowling Green University, Department of Chemistry and Center for Photochemical Sciences, Bowling Green, Ohio 43403 en_US dc.description.abstract Photoexcitation of hexabromoplatinate and hexabromoosmate dianions in CT and ligand field states results in remarkably fast formation (sub 100 fs) of coherently excited photoproducts assigned to $^{3}PtBr_{5}^{-}$ and $^{3}OsBr_{5}^{-}$. This is explained by the fact that one of the lowest triplet excited states in both $PtBr_{6}^{2-}$ and $OsBr_{6}^{2-}$ is repulsive. Surprisingly, the damping time and amplitude of the observed coherent oscillations in the pentabromoosmate (209 cm$^{-1}$) and pentabromoplatinate (112 cm$^{-1}$) species is quite different. The shorter damping time (0.4 ps) of $^{3}PtBr_{5}^{-}$ in comparison with the damping time (1 ps) of $^{3}OsBr_{5}^{-}$ in aqueous solution is related to faster dephasing in $^{3}PtBr_{5}^{-}$. The large-amplitude bending oscillations in pentabromoplatinate are tentatively assigned to the passage of the wavepacket through the Janh-Teller conical intersection(s), whereas in pentabromoosmate, the umbrella type of oscillations appears to be due to the coupling to the Os-Br symmetric stretching mode in the parent dianion. The coherent oscillations in both photoproducts show no dependence on solvent. The results are supported by DFT, TD-DFT and CASSCF/CASPT2 calculations of electronic structures, vertical electronic transitions and harmonic frequencies of initial dianions and photoproducts. en_US dc.language.iso en en_US dc.publisher Ohio State University en_US dc.title ULTRAFAST EXCITED-STATE DYNAMICS IN MODEL HEXABROMOPLATINATE (IV) AND HEXABROMOOSMIATE (IV) DIANIONS IN THE CONDENSED PHASE en_US dc.type Article en_US dc.type Image en_US dc.type Presentation en_US
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