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Ultrafast dynamics of a solution in spatially restricted environments studied by photothermal spectroscopies
Author(s) -
Hirose Yasushi,
Yui Hiroharu,
Sawada Tsuguo
Publication year - 2004
Publication title -
the chemical record
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.61
H-Index - 78
eISSN - 1528-0691
pISSN - 1527-8999
DOI - 10.1002/tcr.20026
Subject(s) - photoisomerization , micelle , chemical physics , relaxation (psychology) , ultrashort pulse , ultrafast laser spectroscopy , picosecond , molecular dynamics , azobenzene , chemistry , absorption (acoustics) , spectroscopy , dynamics (music) , materials science , photochemistry , aqueous solution , computational chemistry , molecule , optics , organic chemistry , physics , isomerization , laser , psychology , social psychology , composite material , catalysis , quantum mechanics , acoustics
The ultrafast dynamics of a solution in spatially restricted environments was studied by using the ultrafast transient lens (UTL) method. The UTL method is used to monitor the molecular dynamics of a solution by means of a change in the refractive index, which is advantageous for investigating the molecular dynamics of restricted systems. We investigated the photoisomerization of azobenzene derivatives in cyclodextrin nanocavities and revealed how the confinement affects the photoisomerization dynamics and yields. We also studied the relaxation dynamics of photo‐excited auramine O (AuO) in a water/aerosol‐OT/ n ‐heptane reversed micelle. Both the perturbed properties of the included water and the interactions between AuO and the interface of the reversed micelle strongly appeared to affect the relaxation dynamics. At the same time, we observed a change in the refractive index suggesting a structural change of the micelles in the picosecond region that could not be detected by transient absorption spectroscopy. In addition, we developed the total internal reflection UTL (TIR‐UTL) method to monitor the ultrafast molecular dynamics at the liquid interface. The relaxation dynamics of photoexcited AuO at the silica/water interface were observed with subpicosecond time resolution, and it was revealed that the interaction with the interface strongly inhibited the relaxation process. These results demonstrated the advantages of the UTL method for investigating the molecular dynamics of a solution in spatially restricted environments. © 2005 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 4: 331–345; 2004: Published online in Wiley InterScience ( www.interscience.wiley.com ) DOI 10.1002/tcr.20026