The trans{cis photoisomerization of azobenzene{containing ma- terials is key to a number of photomechanical applications, but the actual conversion mechanism in condensed phases is still largely un- known. Here we have studied the (n ->pi*) isomerization in vacuum and in various solvents via a modied molecular dynamics simulation adopting an ab initio torsion{inversion force eld in the ground and excited states while allowing for electronic transitions and for a stochastic decay to the fundamental state. We have determined the trans{cis photoisomerization quantum yield and decay times in various solvents (n{hexane, anisole, toluene, ethanol and ethylene glycol), obtaining results comparable with the experimental ones where available. We nd a profound dierence between the isomerization mechanism in vacuum and in solution, with the often neglected mixed torsional{inversion pathway being the most important in solvents
Titolo: | How does the trans-cis photo-isomerization of azobenzene take place in organic solvents? | |
Autore/i: | G. Tiberio; MUCCIOLI, LUCA; BERARDI, ROBERTO; ZANNONI, CLAUDIO | |
Autore/i Unibo: | ||
Anno: | 2010 | |
Rivista: | ||
Digital Object Identifier (DOI): | http://dx.doi.org/10.1002/cphc.200900652 | |
Abstract: | The trans{cis photoisomerization of azobenzene{containing ma- terials is key to a number of photomechanical applications, but the actual conversion mechanism in condensed phases is still largely un- known. Here we have studied the (n ->pi*) isomerization in vacuum and in various solvents via a modied molecular dynamics simulation adopting an ab initio torsion{inversion force eld in the ground and excited states while allowing for electronic transitions and for a stochastic decay to the fundamental state. We have determined the trans{cis photoisomerization quantum yield and decay times in various solvents (n{hexane, anisole, toluene, ethanol and ethylene glycol), obtaining results comparable with the experimental ones where available. We nd a profound dierence between the isomerization mechanism in vacuum and in solution, with the often neglected mixed torsional{inversion pathway being the most important in solvents | |
Data prodotto definitivo in UGOV: | 2010-12-19 19:41:32 | |
Data stato definitivo: | 2017-05-06T14:34:41Z | |
Appare nelle tipologie: | 1.01 Articolo in rivista |