title: Optical Properties of Diarylethenes with TD-DFT: 0-0 Energies, Fluorescence, Stokes Shifts, and Vibronic Shapes.
abstract: This contribution is an investigation of both the structures and optical properties of a set of 14 diverse, recently synthesized diarylethenes using Time-Dependent Density Functional Theory (TD-DFT) at the ωB97X-D/6-31G(d) level of theory. The linear response (LR) and state-specific (SS) versions of the Polarizable Continuum Model (PCM) have been adopted to account for the bulk solvation effects and their relative performances were critically accessed. It is shown, for the first time in the case of nontrivial diarylethenes, that TD-DFT provides good agreement between the experimental absorption-fluorescence crossing points (AFCPs) and their theoretical counterparts when a robust model accounting for both geometrical relaxation and vibrational corrections is used instead of the vertical approximation. On the other hand, the theoretical estimates for the Stokes shifts based on the vertical transition energies were found to be in disagreement with respect to experiment, prompting us to simulate the absorption/emission vibronic band shapes. It is proved that difficulties associated with the breakdown of the harmonic approximation in Cartesian coordinates exist for the investigated system, and we show how they can be at least partially overcome by means of a vertical approach including Duschinsky effects. Our results provide a valuable basis to rationalize the experimental vibronic structure of both emission and absorption bands and are expected to be a significant asset to the understanding of the optical properties of diarylethene derivatives.
authors.affiliation: Laboratoire CEISAM - UMR CNR 6230, Université de Nantes , 2 Rue de la Houssiniére, BP 92208, 44322 Nantes Cedex 3, France.
authors.forename: Agisilaos
authors.initials: A
authors.lastname: Chantzis
authors.affiliation: Departamento de Química Física, Universidad de Murcia , 30110 Murcia, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Cerezo
authors.affiliation: ITODYS, UMR 7086, Université Paris Diderot, Sorbonne Paris Cité , 15 Rue Jean Antoine de Baif, 75205 Paris Cedex 13, France.
authors.forename: Aurélie
authors.initials: A
authors.lastname: Perrier
authors.affiliation: CNR-Consiglio Nazionale delle Ricerche, Istituto di Chimica dei Composti OrganoMetallici (ICCOM-CNR), UOS di Pisa , Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa, Italy.
authors.forename: Fabrizio
authors.initials: F
authors.lastname: Santoro
authors.affiliation: Laboratoire CEISAM - UMR CNR 6230, Université de Nantes , 2 Rue de la Houssiniére, BP 92208, 44322 Nantes Cedex 3, France.|Institut Universitaire de France, 103, bd Saint-Michel, F-75005 Paris Cedex 05, France.
authors.forename: Denis
authors.initials: D
authors.lastname: Jacquemin