Publications de Malte Oppermann

Asymmetric conformation of the high-spin state of iron(II)-tris(2,2-bipyridine): Time-resolved x-ray absorption and ultraviolet circular dichroism

We analyze the structures of the low-spin (LS) ground state and the high-spin (HS) lowest excited state of the iron-(II)-tris bipyridine complex ([Fe(bpy)3]2+) using density functional theory PBE methods, modeling the solvent interactions with conductor-li ...

2024

Disentangling Thermal from Electronic Contributions in the Spectral Response of Photoexcited Perovskite Materials

Majed Chergui, Thomas Charles Henry Rossi, Malte Oppermann, Lijie Wang

Disentangling electronic and thermal effects in photoexcited perovskite materials is crucial for photovoltaic and optoelectronic applications but remains a challenge due to their intertwined nature in both the time and energy domains. In this study, we emp ...

Amer Chemical Soc2024

Early bird or night owl? Controlling the ultrafast photodynamics of triphenylamine substituted 2,2′:6′,2′′-terpyridine

Majed Chergui, Etienne Christophe Socie, Malte Oppermann, Oliviero Cannelli

Controlling the ultrafast photodynamics of metal-free organic molecules has great potential for technological applications. In this work, we use solvent polarity and viscosity as "external knobs" to govern the photodynamics of an electron-donating derivati ...

Royal Soc Chemistry2024

Element- and enantiomer-selective visualization of molecular motion in real-time

Majed Chergui, Malte Oppermann, Jérémy Raymond Jean Maurice Rouxel

Ultrafast optical-domain spectroscopies allow to monitor in real time the motion of nuclei in molecules. Achieving element-selectivity had to await the advent of time resolved X-ray spectroscopy, which is now commonly carried at X-ray free electron lasers. ...

Nature Portfolio2023

Giant two-photon absorption of anatase TiO2 in Au/TiO2 core-shell nanoparticles

Majed Chergui, Malte Oppermann, Lijie Wang

We report on deep-to-near-UV transient absorption spectra of core-shell Au/SiO2 and Au/TiO2 nanoparticles (NPs) excited at the surface plasmon resonance of the Au core, and of UV-excited bare anatase TiO2 NPs. The bleaching of the first excitonic transitio ...

CHINESE LASER PRESS2023

Data for "Ultrafast deep-ultraviolet study of photoexcited aqueous Ferrioxalate"

Majed Chergui, Christoph Bostedt, Michele Puppin, Malte Oppermann, Hui-Yuan Chen

Data repository for the following publication: A. Duque-Prata*, H.-Y. Chen*, L. Müller, M. Oppermann, M. Puppin, C. Serpa, C. Bostedt and M. Chergui, “Ultrafast deep-ultraviolet study of photoexcited aqueous Ferrioxalate”, submitted to ChemPhotoCh ...

Zenodo2023

Exciton decay mechanism in DNA single strands: back-electron transfer and ultrafast base motions

Majed Chergui, Rahul Sharma, Malte Oppermann, Benjamin Bauer

The photochemistry of DNA systems is characterized by the ultraviolet (UV) absorption of pi-stacked nucleobases, resulting in exciton states delocalized over several bases. As their relaxation sensitively depends on local stacking conformations, disentangl ...

ROYAL SOC CHEMISTRY2022

Hard X-ray helical dichroism of disordered molecular media

Majed Chergui, Giulia Fulvia Mancini, Malte Oppermann, Camila Bacellar Cases Da Silveira, Dominik Kinschel, Oliviero Cannelli, Christian David, Jérôme Lacour

Chirality is a structural property of molecules lacking mirror symmetry that has strong implications in diverse fields, ranging from life sciences to materials science. Chirality-sensitive spectroscopic methods, such as circular dichroism, exhibit weak sig ...

Nature Publishing Group2022

Chiral control of spin-crossover dynamics in Fe (II) complexes

Majed Chergui, Malte Oppermann, Jérôme Lacour

Iron-based spin-crossover complexes hold tremendous promise as multifunctional switches in molecular devices. However, real-world technological applications require the excited high-spin state to be kinetically stable-a feature that has been achieved only ...

NATURE PORTFOLIO2022

Slow Charge Carrier Relaxation in Gold Nanoparticles

Majed Chergui, Thomas Charles Henry Rossi, Malte Oppermann, Lars-Hendrik Mewes, Lijie Wang, Benjamin Bauer, Davood Zare

We report on ultrafast transient absorption (TA) studies of surface plasmon-excited similar to 25 nm-diameter Au nanoparticles in solution, monitoring the response of the surface plasmon resonance in the visible region (1.7-3.0 eV) and that of the inter- a ...

AMER CHEMICAL SOC2020