A5008948855- Quantum Chromodynamics and Particle Interactions
- Particle physics theoretical and experimental studies
- Molecular Junctions and Nanostructures
- Nuclear physics research studies
- Graphene research and applications
- Surface Chemistry and Catalysis
- Advanced Chemical Physics Studies
- Force Microscopy Techniques and Applications
- High-Energy Particle Collisions Research
- Quantum and electron transport phenomena
- Advanced NMR Techniques and Applications
- Terahertz technology and applications
- Atomic and Molecular Physics
- Surface and Thin Film Phenomena
- Advanced Combustion Engine Technologies
- Dark Matter and Cosmic Phenomena
- Crystallization and Solubility Studies
- Advanced Electron Microscopy Techniques and Applications
- X-ray Diffraction in Crystallography
- Mass Spectrometry Techniques and Applications
- 2D Materials and Applications
- Semiconductor Quantum Structures and Devices
- Ion-surface interactions and analysis
- Gold and Silver Nanoparticles Synthesis and Applications
- Flexible and Reconfigurable Manufacturing Systems
Fritz Haber Institute of the Max Planck Society
2021-2025
Max Planck Institute for Nuclear Physics
2024
CIC nanoGUNE
2023-2024
Johannes Gutenberg University Mainz
2012-2023
Fraunhofer Institute for Manufacturing Engineering and Automation
2023
University of Stuttgart
2023
Campbell Collaboration
2023
IBM Research - Zurich
2018-2022
Aalto University
2013-2021
University of Zagreb
2017-2021
Carbon allotropes built from rings of two-coordinate atoms, known as cyclo[ n ]carbons, have fascinated chemists for many years, but until now they could not be isolated or structurally characterized because their high reactivity. We generated cyclo[18]carbon (C 18 ) using atom manipulation on bilayer NaCl Cu(111) at 5 kelvin by eliminating carbon monoxide a cyclocarbon oxide molecule, C 24 O 6 . Characterization high-resolution atomic force microscopy revealed polyynic structure with...
A massive, but light, Abelian U(1) gauge boson is a well-motivated possible signature of physics beyond the standard model particle physics. In this Letter, search for signal such in electron-positron pair production at spectrometer setup A1 Collaboration Mainz Microtron described. Exclusion limits mass range 40 MeV/c2 to 300 MeV/c2, with sensitivity squared mixing parameter as little ε2=8×10−7 are presented. large fraction space has been excluded where discrepancy measured anomalous...
The early stages of soot formation, namely inception and growth, are highly debated central to many ongoing studies in combustion research. Here, we provide new insights into these processes from studying different samples by atomic force microscopy (AFM). Soot has been extracted a slightly sooting, premixed ethylene/air flame both at the onset nucleation process, where particle size is order 2–4 nm, initial stage larger particles present. Subsequently, molecular constituents formation were...
Combustion-generated soot particles can have significant impact on climate, environment and human health. Thus, understanding the processes governing formation of in combustion is a topic ongoing research. In this study, high-resolution atomic force microscopy (AFM) was used for direct imaging building blocks forming early stages formation. Incipient were collected right after particle nucleation zone slightly sooting ethylene/air laminar premixed flame at atmospheric pressure analyzed by...
At the Mainz Microtron MAMI, first high-resolution pion spectroscopy from decays of strange systems was performed by electron scattering off a (9)Be target in order to study Λ binding energy light hypernuclei. Positively charged kaons were detected short-orbit spectrometer with broad momentum acceptance at 0° forward angles respect beam, efficiently tagging production strangeness nucleus. Coincidentally, negatively decay pions two independent spectrometers. About 10(3) pionic weak...
On-surface synthesis with molecular precursors has emerged as the de facto route to atomically well-defined graphene nanoribbons (GNRs) controlled zigzag and armchair edges. On Au(111) Ag(111) surfaces, prototypical precursor 10,10′-dibromo-9,9′-bianthryl (DBBA) polymerizes through an Ullmann reaction form straight GNRs However, on Cu(111), irrespective of bianthryl (dibromo-, dichloro-, or halogen-free bianthryl), is inactive, instead, identical chiral are formed. Using resolved noncontact...
Hexagonal boron nitride (h-BN) is a prominent member in the growing family of two-dimensional materials with potential applications ranging from being an atomically smooth support for other to templating growth molecular layers. We have studied structure monolayer h-BN grown by chemical vapor deposition on Ir(111) low-temperature scanning tunneling microscopy (STM) and spectroscopy (STS) experiments state-of-the-art density functional theory (DFT) calculations. The lattice mismatch between...
Cyclo[18]carbon (C18, a molecular carbon allotrope) can be synthesized by dehalogenation of bromocyclocarbon precursor, C18Br6, in 64% yield, atomic manipulation on sodium chloride bilayer Cu(111) at 5 K, and imaged high-resolution force microscopy. This method generating C18 gives higher yield than that reported previously from the cyclocarbon oxide C24O6. The experimental images were compared with simulated for four theoretical model geometries, including possible bond-angle alternation:...
We perform a systematic study of the α-particle excitation from its ground state 0_{1}^{+} to 0_{2}^{+} resonance. The so-called monopole transition form factor is investigated via an electron scattering experiment in broad Q^{2} range (from 0.5 5.0 fm^{-2}). precision new data dramatically supersedes that older sets data, each covering only portion range. allow determination two coefficients low-momentum expansion, leading puzzle. By confronting state-of-the-art theoretical calculations, we...
Using low-temperature scanning tunneling microscopy, we show that monolayer hexagonal boron nitride (h-BN) on Ir(111) acts as ultrathin insulating layer for organic molecules, while simultaneously templating their self-assembly. Tunneling spectroscopy experiments cobalt phthalocyanine (CoPC) reveal narrow molecular resonances and indicate the charge state of CoPC is periodically modulated by h-BN moiré superstructure. Molecules in second site-selective adsorption behavior, allowing synthesis...
The electronic properties of graphene edges have been predicted to depend on their crystallographic orientation. so-called zigzag (ZZ) haven extensively explored theoretically and proposed for various applications. However, experimental study remains challenging due the difficulty in realizing clean ZZ without disorder, reconstructions, or presence chemical functional groups. Here, we propose ZZ-terminated, atomically sharp interfaces between hexagonal boron nitride (BN) as experimentally...
A route to generate cyclacenes by on-surface synthesis is explored. We started synthesizing two tetraepoxycyclacenes sequences of Diels-Alder cycloadditions. Subsequently, these molecules were deposited onto Cu(111) and scanning-tunneling-microscopy(STM)-based atom manipulation was employed dissociate the oxygen atoms. Atomic force microscopy (AFM) with CO-functionalized tips enabled detailed characterization reaction products revealed that, at most, oxygens per molecule could be removed....
Soot emitted from incomplete combustion of hydrocarbon fuels contributes to global warming and causes human disease. The mechanism by which soot nanoparticles form within flames is still an unsolved problem in science. Mechanisms proposed date involving purely chemical growth are limited slow reaction rates, whereas mechanisms relying on solely physical interactions between molecules weak intermolecular that unstable at flame temperatures. Here, we show evidence for a reactive π-diradical...
π-conjugated organic molecules tend to adsorb in a planar configuration on graphene irrespective of their charge state. In contrast, here we demonstrate charging-induced strong structural relaxation tetrafluorotetracyanoquinodimethane (F4TCNQ) epitaxial Ir(111) (G/Ir(111)). The work function modulation over the moiré unit cell causes site-selective charging F4TCNQ. Upon charging, molecule anchors face-centered cubic sites G/Ir(111) through one or two cyano groups. reaction is reversible and...
Determination of the molecular structures petroporphyrins has been crucial to understand diagenetic pathways and maturation petroleum. However, these studies have hampered by their structural complexity challenges associated with isolation. In comparison skeletal macrocyclic structures, much less is known about substitutions, which are more sensitive diagenesis pathways. While isolated vanadyl largely consist etioporphyrin deoxophylloerythroetioporphyrin as expected, surprisingly, we find...
We report on a new experimental method based initial-state radiation (ISR) in e–p scattering, which exploits the radiative tail of elastic peak to study properties electromagnetic processes and extract proton charge form factor (GEp) at extremely small Q2. The ISR technique was implemented an experiment three-spectrometer facility Mainz Microtron (MAMI). This led precise validation corrections far away from line provided first measurements GEp for 0.001≤Q2≤0.004(GeV/c)2.
Atomic force microscopy (AFM) with molecule-functionalized tips has emerged as the primary experimental technique for probing atomic structure of organic molecules on surfaces. Most experiments have been limited to nearly planar aromatic due difficulties interpretation highly distorted AFM images originating from nonplanar molecules. Here, we develop a deep learning infrastructure that matches set unique descriptor characterizing molecular configuration, allowing us predict directly. We...
Triangulenes are a class of open-shell triangular graphene flakes with total spin increasing their size. In the last years, on-surface-synthesis strategies have permitted fabricating and engineering triangulenes various sizes structures atomic precision. However, direct proof size remains elusive. this work, we report combined in-solution on-surface synthesis large nitrogen-doped triangulene (aza-[5]-triangulene) on Au(111) surface, detection its high-spin ground state. Bond-resolved...
Controlling light emission from plasmonic nanojunctions is crucial for developing tunable nanoscale sources and integrated photonic applications. It requires precise engineering of nanocavity electrodes a detailed understanding electrically driven emission. Using scanning tunneling microscopy-induced luminescence (STML), we studied ultrathin ZnO/Ag(111) inside silver nanocavity. At positive bias, luminescence, caused by radiative decay localized surface plasmons (LSP), spectrally low-pass...
There are currently no experimental techniques that combine atomic-resolution imaging with elemental sensitivity and chemical fingerprinting on single molecules. The advent of using molecular-modified tips in noncontact atomic force microscopy (nc-AFM) has made it possible to image (planar) molecules resolution. However, the mechanisms responsible for contrast passivated not fully understood. Here, we investigate by carrying out both nc-AFM Kelvin probe (KPFM) experiments epitaxial monolayer...
Abstract The combination of several materials into heterostructures is a powerful method for controlling material properties. integration graphene (G) with hexagonal boron nitride (BN) in particular has been heralded as way to engineer the band structure and implement spin- valleytronics 2D materials. Despite recent efforts, fabrication methods well-defined G-BN structures on large scale are still lacking. We report new producing atomically an unprecedented length by exploiting interaction G...
Abstract Dissolved organic carbon (DOC) is the largest pool of exchangeable in ocean. However, less than 10% DOC has been molecularly characterized deep ocean to understand DOC's recalcitrance. Here we analyze radiocarbon ( 14 C) depleted, and presumably refractory, low molecular weight (LMW) from North Central Pacific using atomic force microscopy produce first atomic‐resolution images individual LMW molecules. We evaluate surface chemical structures context their relative persistence...
Here we present a new method that integrates atomic force microscopy (AFM) with analytical tools such as high-performance liquid chromatography (HPLC) diode-array ultraviolet–visible (UV) absorbance, and mass spectrometry (MS) along synthetic chemistry. This allows the detection, identification, quantification of novel polycyclic aromatic hydrocarbons (PAH) in complex molecular mixtures. multidisciplinary methodology is employed to characterize supercritical pyrolysis products n-decane,...