Publications de Lars-Hendrik Mewes

Broadband visible two-dimensional spectroscopy of molecular dyes

Majed Chergui, Andre Al Haddad, Lars-Hendrik Mewes, Rebecca Ann Ingle

Two-dimensional Fourier transform spectroscopy is a promising technique to study ultrafast molecular dynamics. Similar to transient absorption spectroscopy, a more complete picture of the dynamics requires broadband laser pulses to observe transient change ...

AMER INST PHYSICS2021

Energy relaxation pathways between light-matter states revealed by coherent two-dimensional spectroscopy

Majed Chergui, Lars-Hendrik Mewes, Rebecca Ann Ingle

Coupling matter excitations to electromagnetic modes inside nano-scale optical resonators leads to the formation of hybrid light-matter states, so-called polaritons, allowing the controlled manipulation of material properties. Here, we investigate the phot ...

NATURE RESEARCH2020

Photoemission from non-polar aromatic molecules in the gas and liquid phase

Majed Chergui, Frank van Mourik, Christopher Alexander Arrell, Lars-Hendrik Mewes, José Javier Pancracio Ojeda Andara, Jakob Grilj, Luca Longetti

The photoelectron spectra of both liquid and gas phase aromatic molecules are reported. The spectra were obtained using a 34.1 eV source produced by high harmonic generation and analysed with the help of high-level ab initio simulations using the reflectio ...

ROYAL SOC CHEMISTRY2020

Ultrafast Intersystem Crossing and Structural Dynamics of [Pt(ppy)(mu-(t)Bu(2)pz)](2)

Majed Chergui, Lars-Hendrik Mewes, Rebecca Ann Ingle

Intersystem crossing (ISC) rates of transition-metal complexes are determined by the complex interplay of a molecule's electronic and structural dynamics. To broaden our understanding of these key factors, we investigate the case of the prototypical d(8)-d ...

2020

Slow Charge Carrier Relaxation in Gold Nanoparticles

Majed Chergui, Lars-Hendrik Mewes, Thomas Charles Henry Rossi, Lijie Wang, Malte Oppermann, 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

Non-equilibrium dynamics of di-platinum complexes and molecular dyes in solution: Insights from transient absorption and two-dimensional Fourier transform spectroscopy

Lars-Hendrik Mewes

Unraveling the interplay between electronic- and vibrational degrees of freedom on the earliest time scales of physical, chemical and biological processes is crucial to gaining insight into the mechanisms that govern the world around us, since it is during ...

EPFL2019

Localized holes and delocalized electrons in photoexcited inorganic perovskites: Watching each atomic actor by picosecond X-ray absorption spectroscopy

Majed Chergui, Andre Al Haddad, Lars-Hendrik Mewes, Thomas Charles Henry Rossi, Gloria Capano, Jakob Grilj, Fabio Giacomo Santomauro, Dominik Kinschel, James Michael Budarz

We report on an element-selective study of the fate of charge carriers in photoexcited inorganic CsPbBr3 and CsPb(ClBr)(3) perovskite nanocrystals in toluene solutions using time-resolved X-ray absorption spectroscopy with 80 ps time resolution. Probing th ...

Amer Inst Physics2017

The LOUVRE Laboratory: State-of-the-Art Ultrafast Ultraviolet Spectroscopies for Molecular and Materials Science

Majed Chergui, Frank van Mourik, Natalia Nagornova, Lars-Hendrik Mewes, Thomas Charles Henry Rossi, Tania Palmieri, Edoardo Baldini, Malte Oppermann, Benjamin Bauer, Aurelio Oriana

We describe the facilities for ultraviolet studies in the femtosecond to nanosecond time domain. These facilities consist of: i) a set-up for deep-ultraviolet spectroscopy in the 260–380 nm range in both pump and probe pulses for transient absorption/refle ...

2017

Harmonium: A pulse preserving source of monochromatic extreme ultraviolet (30–110 eV) radiation for ultrafast photoelectron spectroscopy of liquids

Majed Chergui, Frank van Mourik, Christopher Alexander Arrell, Hua Zhang, Lars-Hendrik Mewes, José Javier Pancracio Ojeda Andara, Jakob Grilj

A tuneable repetition rate extreme ultraviolet source (Harmonium) for time resolved photoelectron spectroscopy of liquids is presented. High harmonic generation produces 30-110 eV photons, with fluxes ranging from similar to 2 x 10(11) photons/s at 36 eV t ...

Amer Inst Physics2016

Laser-Assisted Photoelectric Effect from Liquids

Majed Chergui, Frank van Mourik, Christopher Alexander Arrell, Lars-Hendrik Mewes, José Javier Pancracio Ojeda Andara, Jakob Grilj

The laser-assisted photoelectric effect from liquid surfaces is reported for the first time. Photoelectrons generated by 35.6 eV radiation from a liquid microjet of water under vacuum are dressed with (h) over bar omega = 1.55 eV laser field. The subsequen ...

American Physical Society2016

Precise Control of Intramolecular Charge-Transport: The Interplay of Distance and Conformational Effects

Jacques-Edouard Moser, Mateusz Barnaba Wielopolski, Lars-Hendrik Mewes

A new series of donor–bridge–acceptor (D–B–A) compounds consisting of π-conjugated oligofluorene (oFL) bridges between a ferrocene (Fc) electron-donor and a fullerene (C60) electron-acceptor have been synthesized. In addition to varying the length of the b ...

Wiley-Blackwell2013