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Reaction dynamics photoisomerization

We have presented the first published results of a QM/MM wavepacket dynamics study of a photochemical reaction. The photoisomerization mechanism for the GFP chromophore that we observe has the signatures of HT motion, even in the complete absence of an environment. The HT mechanism is aborted in both the gas phase and solution, but the... [Pg.430]

H. Hamaguchi I would like to comment on the stilbene photoisomerization in solution. We recently found an interesting linear relationship between the dephasing time of the central double-bond stretch vibration of Si franj-stilbene, which was measured by time-resolved Raman spectroscopy, and the rate of isomerization in various solutions. Although the linear relationship has not been established in an extensive range of the isomerization rate, I can point out that the vibrational dephasing time measured by Raman spectroscopy is an important source of information on the solvent-induced vibrational dynamics relevant to the reaction dynamics in solution. [Pg.404]

One example of non-IRC trajectory was reported for the photoisomerization of cA-stilbene.36,37 In this study trajectory calculations were started at stilbene in its first excited state. The initial stilbene structure was obtained at CIS/6-31G, and 2744 argon atoms were used as a model solvent with periodic boundary conditions. In order to save computational time, finite element interpolation method was used, in which all degrees of freedom were frozen except the central ethylenic torsional angle and the two adjacent phenyl torsional angles. The solvent was equilibrated around a fully rigid m-stilbene for 20 ps, and initial configurations were taken every 1 ps intervals from subsequent equilibration. The results of 800 trajectories revealed that, because of the excessive internal potential energy, the trajectories did not cross the barrier at the saddle point. Thus, the prerequisites for common concepts of reaction dynamics such TST or RRKM theory were not satisfied. [Pg.191]

Chosrowjan, H. Taniguchi, S. Malaga, N. Hamada, N. Tokunaga, F. Imamoto, Y Kataoka, M. Coherent oscillations in photoisomerization reaction dynamics of photoactive yellow protein (PYP) and related systems. Trends Opt. Photonics 2002, 72, 380-381. [Pg.248]

Syage J A, Felker P M and Zewail A H 1984 Picosecond dynamics and photoisomerization of stiibene in supersonic beams, ii. Reaction rates and potentiai energy surface J. Chem. Phys. 81 4706-23... [Pg.867]

Fig. 1. Idealized photoisomerization mechanisms. These can lead to different final products as shown. However, one should realize that hot ground state reactions could also occur, obscuring a simple relationship between products and excited state dynamics. Fig. 1. Idealized photoisomerization mechanisms. These can lead to different final products as shown. However, one should realize that hot ground state reactions could also occur, obscuring a simple relationship between products and excited state dynamics.
Several years ago, we found that the isomerization of n-butylammonium ( Z,Z)-muconate produces the corresponding EE-isomer in a high yield in the crystalline state under photoirradiation [41]. This solid-state photoisomerization was re e e< t0 he a one-way reaction and no EZ-isomer was formed during the reaction, unsaturated compounds such as olefins, polyenes, and azo compounds generally undergo reversible one-bonded photoisomerization to form a mixture of omers. Previously, we pointed out the possibility that the isomerization of the but thni(i er Va ves the s°hd state f°ll°ws the bicycle-pedal reaction mechanism, et al [4 eta s °ffhe molecular dynamics ofthe reaction had not been clarified. Saltiel react an< fl have independently discussed volume-conserving... [Pg.179]

The photoisomerization dynamics of diphenylbutadiene in both liquid and solid alkane environments has been analyzed in paper which is one contribution to the complete journal issue on the role of solvents in liquid state reactions. Several related topics of photophysical interest are discussed in this collection of papers. [Pg.20]


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See also in sourсe #XX -- [ Pg.183 , Pg.184 , Pg.185 , Pg.186 , Pg.187 , Pg.188 , Pg.189 , Pg.190 ]




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