Ab Initio Calculation of the Electronic Spectrum of Azobenzene Dyes and Its Impact on the Design of Optical Data Storage Materials

Abstract

Electronic excitation energies of 16 azobenzene dyes have been calculated by ab initio methods within the second-order polarization propagator approximation (SOPPA). Good agreement with expriment is found for the lowest singlet and triplet states for both the trans-and cis-azobenzene molecules. The differences are in the range of (0.3 eV, with the exception of the lowest n f π * transition in trans-azobenzene, where a deviation of -0.64 eV is found. The lowest π f π * transition in trans-azobenzene, on the other hand, is particularly well reprensented with a deviation of only -0.15 eV. Furthermore, the experimental singlet π f π * transitions are reproduced for a set of azobenzene dyes with different electron donor and acceptor groups and the correct shifts in excitation energy are obtained for the different substituents. It has also been demonstrated that ab initio methods can be used to determine suitable candidates for azo components used in materials for data storage.

Optical properties of azobenzene-functionalized self-assembled monolayers: Intermolecular coupling and many-body interactions

“…The excitation energies of the molecule considered here are lower by a few hundred meV compared to those reported in the literature for bare trans-azobenzene. 52,53,[55][56][57] This is expected, since the presence of the oxygen-based group terminating the molecule (see Fig. 1a) is known to cause a red-shift of the π-π * transitions.…”

Mechanism and Dynamics of Azobenzene Photoisomerization

“…Its photoisomerization is the basis for many functional materials with applications in photonics 1 and data storage, 2 as a trigger for protein folding, 3 and as probes of local environment. 4 Although the isomerization proceeds without detectable side reactions, the quantum yield (φ isom ) displays an unusual wavelength dependence, which violates Kasha's rule.…”

Reversible light‐induced wettability of fluorine‐containing azobenzene‐derived Langmuir–Blodgett films

“…Films were prepared on a computercontrolled Langmuir trough (KSV-5000). The compound was dissolved in chloroform at a concentration of 7.9 ð 10 4 mol l 1 . An appropriate amount of the spreading solution was carefully injected onto the air-water interface.…”

“…After the chloroform solvent was evaporated off for 15 min, the monolayers were transferred onto solid substrates by vertical lifting. The pressure was kept constant at 10 mN m 1 . Ultraviolet (UV)-Vis absorption spectra were taken with a U-3010 spectrophotometer.…”