Goals and Approaches
  • Photodynamical simulations including nonadiabatic effects and all internal degrees of freedom
  • On-the-fly approach based on multireference methods
  • Nonadiabatic dynamics using time-derivative coupling and single-reference meghods (TD-DFT, ADC(2))
  • Inclusion of environment via QM/MM approach
    Analytic MRCI gradients for excited states and nonadiabatic couplings using the COLUMBUS program system
    Tully surface hopping using NEWTON-X


Collaboration partner: Mario Barbatti (Université Aix-Marseille, Marseille, France)

The photodynamics of DNA

Isolated bases
M. Barbatti, A. J. A. Aquino, J. J. Szymczak, D. Nachtigallová, P. Hobza, and H. Lischka
PNAS 107, 21453 (2010)

The influence of interstrand hydrogen bonding on the photodynamics of cytosine and guanine
T. Zelený, M. Ruckenbauer, A. J.A. Aquino, Th. Müller, F. Lankaš, T. Dršata, W. L. Hase, D. Nachtigallova and H. Lischka
JACS 134, 13662 (2012)

Excimers in stacked nucleobases
F. Plasser, and H. Lischka
Photochem. Photobiol. Sci, 12, 1440 (2013)

H. Lischka, M. Barbatti, F. Siddique, A. Das, A. J. A. Aquino The effect of hydrogen bonding on the nonadiabatic dynamics of a thymine-water cluster, Chem. Phys. 515 (2018) 472 Surface hopping photodynamics simulations have been performed on a cluster of thymine interacting with six water molecules (T(H2O)6). Comparison with the previously performed photodynamics for the isolated thymine (Molecules 21 (2016) 1603) shows a similar global behavior and the central role of the S1(nπ*) minimum for further long-term dynamics. The main difference comes from the destabilization of the np* state by hydrogen bonding, which leads to a significantly enhanced conversion rate from the bright S2(ππ*) state to S1(nπ*) for the T(H2O)6 cluster.
gas phase dynamics
water cluster

F. Siddique, M. Barbatti, Zh. Cui, H. Lischka, A. J. A. Aquino

Nonadiabatic Dynamics of Charge-Transfer States Using the Anthracene−Tetracyanoethylene Complex as a Prototype

J. Phys. Chem. A 124 (2020) 3347

Starting from the bright local excited (LE) state of anthracene, the complex returns to the neutral ground state in gas phase, whereas in water a competing deactivation pathway to an ion pair in the ground state exists

Y. Li, A. J. A. Aquino, F. Siddique, Th. A. Niehaus, H. Lischka, D. Nachtigallová

Pathways to fluorescence via restriction of intramolecular motion in substituted tetraphenylethylenes

PhysChemChemPhys 24 (2022) 1722 – 1735

Restricted access to conical intersection (RACI) is the key to enhancing emission intensities by blocking competing and unproductive non-radiative relaxation pathways. This work investigates the effect of functionalization of tetraphenylethylene (TPE) by means of surface hopping investigations to achieve this goal.

Rafael S. Mattos, Irene Burghardt, Adelia J. A. Aquino, Thiago M. Cardozo, Hans Lischka

On the Cooperative Origin of Solvent-Enhanced Symmetry-Breaking Charge Transfer in a Covalently Bound Tetracene Dimer Leading to Singlet-Fission

J. Amer. Chem. Soc. 144 (2022) 23492–23504

Singlet fission in covalently bound acene dimers in solution is driven by the interplay of excitonic and singlet correlated triplet (1TT) states with intermediate charge-transfer states, a process which depends sensitively on the solvent environment. It is shown that several types of symmetry-breaking inter- and intra-fragment vibrations play a crucial role in a concerted mechanism with the solvent environment and with the symmetric intramolecular inter-fragment torsion, which tunes the admixture of excitonic and charge transfer states. This offers a new perspective on how solvent-induced symmetry-breaking charge transfer can be understood and how it cooperates with intramolecular mechanisms in singlet fission.