On the Low-Lying Electronically Excited States of Azobenzene Dimers: Transition Density Matrix Analysis

Azobenzene-containing molecules may associate with each other in systems such as self-assembled monolayers or micelles. The interaction between azobenzene units leads to a formation of exciton states in these molecular assemblies. Apart from local excitations of monomers, the electronic transitions to the exciton states may involve charge transfer excitations. Here, we perform quantum chemical calculations and apply transition density matrix analysis to quantify local and charge transfer contributions to the lowest electronic transitions in azobenzene dimers of various arrangements. We find that the transitions to the lowest exciton states of the considered dimers are dominated by local excitations, but charge transfer contributions become sizable for some of the lowest ππ* electronic transitions in stacked and slip-stacked dimers at short intermolecular distances. In addition, we assess different ways to partition the transition density matrix between fragments. In particular, we find that the inclusion of the atomic orbital overlap has a pronounced effect on quantifying charge transfer contributions if a large basis set is used.

On the Low-Lying Electronically Excited States of Azobenzene Dimers: Transition Density Matrix Analysis

Azobenzene-containing molecules may associate with each other in systems such as self-assembled monolayers or micelles. The interaction between azobenzene units leads to a formation of exciton states in these molecular assemblies. Apart from local excitations of monomers, the electronic transitions to the exciton states may involve charge transfer excitations. Here, we perform quantum chemical calculations and apply transition density matrix analysis to quantify local and charge transfer contributions to the lowest electronic transitions in azobenzene dimers of various arrangements. We find that the transitions to the lowest exciton states of the considered dimers are dominated by local excitations, but charge transfer contributions become sizable for some of the lowest ππ* electronic transitions in stacked and slip-stacked dimers at short intermolecular distances. In addition, we assess different ways to partition the transition density matrix between fragments. In particular, we find that the inclusion of the atomic orbital overlap has a pronounced effect on quantifying charge transfer contributions if a large basis set is used.

Theoretical study of the electric and the magnetic dipole in UV-Vis and ECD of fluralaner: the folded conformation and the extended conformation

In our contribution, we have carried out a theoretical study of the transition characteristics of one-photon absorption (OPA) spectra of the folded conformation and the extended conformation of fluralaner. The electronic transitions in OPA are visualized with charge difference density (CDD) and transition density matrix (TDM) to explain the charge transfer via hole-electron distribution. We also analyze the transition dipole electric/ magnetic moment by using the isosurface (real space) and TDM diagram in order to determine the portions of molecules which have the most contribution in ECD spectra.

Designing of 5,10-Dihydroindolo [3,2-b] Indole (DINI) Based Donor Materials for Small Molecule Organic Solar Cells

In this paper, four small molecules B1, B2, B3 and B4 based on donor–acceptor–donor–acceptor–donor (D-A-D-A-D) combination were designed by making structural modifications in R. The designed molecules contain 5,10-dihydro-indolo [3,2-b] indole central donor core and different benzo-thiadiazole and fluorine substituted benzothiadiazole (FBT) acceptor units. These molecules have different subunits introduced on 5,10-dihydroindolo [3,2-b] indole central core like benzo [1,2,5] thiadiazole in (B1), 5-Fluoro-benzo [1,2,5] thiadiazole in (B2), 5-Methyl-benzo [1,2,5] thiadiazole in (B3), 2-Fluoro-2-methyl-2-H-benzotriazole unit in (B4), flanked with [2,2’,5’,2”] terthiophene as spacer (S) and triphenyl amine as a common end-capped donor in all the molecules (B1–B4). The optoelectronic properties of these molecules were studied by performing density functional theory (DFT) at CAM-B3LYP. Among all the designed structures, B2 showed maximum absorption (457[Formula: see text]nm) due to its strong electron withdrawing 5-Fluoro-benzo [1,2,5] thiadiazole acceptor unit. Other opto-electronic properties were analyzed through reorganization energies, density of electronic states and transition density matrix (TDM) to estimate the photovoltaic potential of these newly designed molecules. Low exciton binding energies and comparable values of open circuit voltage than R indicate the worth of these candidates to be used in future solar energy driven devices.

Excited state analysis of absorption processes in metal decorated graphene nanoribbons

Transition density matrix (TDM) based excited state analysis presented for single metal atom doped graphene C29H14-X. Natural transition orbitals (NTOs) and e–h correlation plots of Ti-doped graphene are shown below.