@article{HocheFlockMiaoetal.2021, author = {Hoche, Joscha and Flock, Marco and Miao, Xincheng and Philipp, Luca Nils and Wenzel, Michael and Fischer, Ingo and Mitric, Roland}, title = {Excimer formation dynamics in the isolated tetracene dimer}, series = {Chemical Science}, volume = {12}, journal = {Chemical Science}, number = {36}, doi = {10.1039/D1SC03214C}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-251559}, pages = {11965 -- 11975}, year = {2021}, abstract = {The understanding of excimer formation and its interplay with the singlet-correlated triplet pair state \(^{1}\)(TT) is of high significance for the development of efficient organic electronics. Here, we study the photoinduced dynamics of the tetracene dimer in the gas phase by time-resolved photoionisation and photoion imaging experiments as well as nonadiabatic dynamics simulations in order to obtain mechanistic insight into the excimer formation dynamics. The experiments are performed using a picosecond laser system for excitation into the S\(_{2}\) state and reveal a biexponential time dependence. The time constants, obtained as a function of excess energy, lie in the range between ≈10 ps and 100 ps and are assigned to the relaxation of the excimer on the S\(_{1}\) surface and to its deactivation to the ground state. Simulations of the quantum-classical photodynamics are carried out in the frame of the semi-empirical CISD and TD-lc-DFTB methods. Both theoretical approaches reveal a dominating relaxation pathway that is characterised by the formation of a perfectly stacked excimer. TD-lc-DFTB simulations have also uncovered a second relaxation channel into a less stable dimer conformation in the S\(_{1}\) state. Both methods have consistently shown that the electronic and geometric relaxation to the excimer state is completed in less than 10 ps. The inclusion of doubly excited states in the CISD dynamics and their diabatisation further allowed to observe a transient population of the \(^{1}\)(TT) state, which, however, gets depopulated on a timescale of 8 ps, leading finally to the trapping in the excimer minimum.}, language = {en} } @article{GerlachMonningerSchleieretal.2021, author = {Gerlach, Marius and Monninger, Sophie and Schleier, Domenik and Hemberger, Patrick and Goettel, James T. and Braunschweig, Holger and Fischer, Ingo}, title = {Photoelectron Photoion Coincidence Spectroscopy of NCl\(_{3}\) and NCl\(_{2}\)}, series = {ChemPhysChem}, volume = {22}, journal = {ChemPhysChem}, number = {21}, doi = {10.1002/cphc.202100537}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257322}, pages = {2164-2167}, year = {2021}, abstract = {We investigate NCl\(_{3}\) and the NCl\(_{2}\) radical by photoelectron-photoion coincidence spectroscopy using synchrotron radiation. The mass selected threshold photoelectron spectrum (ms-TPES) of NCl\(_{3}\) is broad and unstructured due to the large geometry change. An ionization energy of 9.7±0.1 eV is estimated from the spectrum and supported by computations. NCl2 is generated by photolysis at 213 nm from NCl\(_{3}\) and its ms-TPES shows an extended vibrational progression with a 90 meV spacing that is assigned to the symmetric N-Cl stretching mode in the cation. An adiabatic ionization energy of 9.94 ± 0.02 eV is determined.}, language = {en} }