Ultrafast Time-Resolved Vibrational Spectroscopy at University of Zurich

Abstract

Vibrational spectroscopy uniquely combines ultrafast time-resolution with chemical selectivity and molecular structure resolution. A list of examples of experiments and applications pursued at University of Zurich highlights the wide-spread applicability of time-resolved vibrational spectroscopy for molecular sciences. NCCR MUST

Tuning charge carrier dynamics through spacer cation functionalization in layered halide perovskites: an ab initio quantum dynamics study

“…is the unnormalized autocorrelation function (u-ACF), defined as C ij (t) = hdE ij (t)dE ij (0)i, dE ij (t) = E ij (t) À hE ij i is the fluctuation of the energy gap between the i and jth states from the canonical ensemble average value. 122,123 Due to considerably large computational expenses, we ignore the effect of SOC though it can have a systematic influence on the non-radiative charge recombination process. 124 Furthermore, the exclusion of excitonic effects during our simulations of LHPs is also another noteworthy approximation.…”

Impact of composition engineering on charge carrier cooling in hybrid perovskites: computational insights

“…The mixed quantum-classical non-adiabatic molecular dynamics (NAMD) simulations with the decoherence-induced surface hopping (DISH) technique have been adapted to investigate the nonadiabatic transitions of hot carriers. 47,74,75 The NAMD simulations use the framework of time-domain density functional theory (DFT) as implemented in the PYthon eXtension for Ab Initio Dynamics (PYXAID) code. 49,61,76 Within this methodology we consider the electrons as the quantum mechanical particle and nuclei as the classical entity.…”

Optoelectronic Properties of Two-Dimensional Bromide Perovskites: Influences of Spacer Cations

“…Following that, we generate 4 ps trajectories in the microcanonical ensemble and used these for the nonadiabatic coupling simulations. We considered all 4000 geometries along the trajectories and 1000 stochastic realizations of the DISH process for each geometry to evaluate the electron–hole recombination as implemented in the PYthon eXtension for Ab Initio Dynamics code. , We further calculate the pure-dephasing time as considered in the optical-response theory for evaluating the decoherence time for these materials . Even though recent work points out the importance of SOC in nonradiative charge recombination, we have not included such an effect in our simulations due to very high computational cost .…”