The electronic and molecular structure of N,N,N',N'-tetraphenylphenylenediamine radical cation 1(+) is in focus of this study. Resonance Raman experiments showed that at least eight vibrational modes are strongly coupled to the optical charge resonance band which is seen in the NIR. With the help of a DFT-based vibrational analysis, these eight modes were assigned to symmetric vibrations. The contribution of these symmetric modes to the total vibrational reorganization energy is dominant. These findings are in agreement with the conclusions from a simple two-state two-mode Marcus-Hush analysis which yields a tiny electron-transfer barrier. The excellent agreement of the X-ray crystal structure analysis and the DFT computed molecular structure of 1(+) on one hand as well as the solvent and solid-state IR spectra and the DFT-calculated IR active vibrations on the other hand prove 1(+) adopts a symmetrical delocalized Robin-Day class III structure both in the solid state and in solution.

We study the quantum dynamics in a model system consisting of two electrons and a nucleus which move between two fixed ions in one dimension. The numerically determined wave functions allow for the calculation of time-dependent electron localization functions in the case of parallel spin and of the time-dependent antiparallel spin electron localization functions for antiparallel spin. With the help of these functions, it becomes possible to illustrate how electronic localization is modified through the vibrational wave-packet motion of the nucleus.

We investigate the correlated electronic and nuclear motion in a model system as proposed by Shin and Metiu [J. Chem. Phys. 102, 9285 (1995)]. The quantum dynamics is studied during laser induced electronic transitions. Here, the influence of nonadiabatic coupling on the absorption spectrum is investigated and the Franck-Condon principle is illustrated in terms of the temporal changes of electronic and nuclear densities. In the case of intense field excitation, multiphoton processes become important, and electronic as well as vibrational wave packets are prepared.

A bound-to-free transition initiated by femtosecond excitation of diatomic molecules results in photofragments with a distribution of kinetic energies. A measurement of the kinetic-energy distribution yields the modulus squared of the asymptotic momentum-space wave packet prepared in the laser excitation process. On the other hand, the coordinate-space density of the wave packet entering the interaction-free region can be determined from pump–probe integrated fluorescence spectroscopy. We provide several numerical examples to show that this information can be used to determine the phase of the asymptotic wave packet so that this particular quantum-mechanical wave function can be characterized completely. To achieve this aim we use an iteration scheme (Gerchberg–Saxton algorithm) which does not require any further information about the system or the laser pulses.