A5041122842- Spectroscopy and Quantum Chemical Studies
- Laser-Matter Interactions and Applications
- Advanced Chemical Physics Studies
- Mass Spectrometry Techniques and Applications
- Molecular spectroscopy and chirality
- Photoreceptor and optogenetics research
- Advanced Fiber Laser Technologies
- Laser Design and Applications
- Photochemistry and Electron Transfer Studies
- Terahertz technology and applications
- High-Energy Particle Collisions Research
- Laser-induced spectroscopy and plasma
- Silicon and Solar Cell Technologies
- Stochastic processes and statistical mechanics
- Spectroscopy and Chemometric Analyses
- Atomic and Molecular Physics
- Particle Accelerators and Free-Electron Lasers
- Receptor Mechanisms and Signaling
- Spectroscopy Techniques in Biomedical and Chemical Research
- DNA and Nucleic Acid Chemistry
- Analytical chemistry methods development
- Particle accelerators and beam dynamics
- Theoretical and Computational Physics
- Advanced X-ray and CT Imaging
- Nuclear Physics and Applications
University of Kassel
2014-2025
K+S (Germany)
2020
Circular dichroism (CD) in ion yield the gas phase is a promising chiral recognition technique. Combining it with broadband ultrafast laser pulses allows us to examine possibility of coherent control. We used shaped femtosecond control CD 3-methylcyclopentanone observed from 1 + resonance-enhanced multiphoton ionisation around 309 nm. The duration increased via their spectral width or frequency chirp, and pulse pair adjustable delay employed study effect on yield. Furthermore, we strongly...
The direct manipulation of charge oscillations has emerged as a new perspective in chemical reaction control. Here, we demonstrate, joint experimental and theoretical study, that the electron dynamics molecule is efficiently steered by controlling interplay driving femtosecond laser pulse with photoinduced oscillation. These have typical Bohr period around 1 fs for valence electrons; therefore, control to be exerted on shorter time scale. Specifically, show how precision shaping used...
We investigate the differential ionization probability of chiral molecules in strong field regime as a function helicity incident light. To this end, we analyze fourfold bromochlorofluoromethane (CHBrClF) with subsequent fragmentation into four charged fragments and different dissociation channels singly ionized methyloxirane. observe variation range several percent. Accordingly, conclude that light is quantity should be considered for theoretical description rate molecules.
Recently we have demonstrated control of valence-bond excitation a molecule due to the interplay induced charge oscillation with precisely tailored phase driving laser field (Bayer et al 2013 Phys. Rev. Lett. 110 123003). In this contribution describe in more detail two-colour experiment—a pulse sequence followed by an ionizing probe different wavelength. We provide details on quantum dynamics simulations carried out reproduce and analyse experimental results. The procedure for averaging...
By combining molecular beam techniques with high resolution resonance enhanced multi photon ionization followed by angular resolved photoelectron detection we pave the way for enantiomer specific identification in multi-component mixtures.
Quantum chemical calculations of one‐photon absorption, electronic circular dichroism and anisotropy factor spectra for the A‐band transition fenchone, camphor 3‐methylcyclopentanone (3MCP) are reported. While only weakly allowed nature leads to comparatively large anisotropies, a proper theoretical description absorption such requires account non‐Condon effects. We present experimental data 3MCP in liquid phase show that corresponding Herzberg–Teller corrections critical reproduce main...
In the treatment of most newly discovered solid cancerous tumors, surgery remains first option. An important factor in success these operations is precise identification oncological safety margins to ensure complete removal tumor without affecting much neighboring healthy tissue. Here we report on possibility applying femtosecond Laser-Induced Breakdown Spectroscopy (LIBS) combined with Machine Learning algorithms as an alternative discrimination technique differentiate The emission spectra...
The combination of circular dichroism with laser mass spectrometry via the measurement ion yields is a powerful tool in chiral recognition, but measured anisotropies are generally weak. method presented this contribution reduces error significantly. A common path optical setup generates pair counter-rotating foci interaction region time-of-flight spectrometer. As space focus condition fulfilled for both individually, becomes twin-peak source well separated and sufficiently resolved peaks....
Photoelectron circular dichroism (PECD) is a fascinating phenomenon both from fundamental science aspect but also due to its emerging role as highly sensitive analytic tool for chiral recognition in the gas phase. PECD has been studied with single-photon well multi-photon ionization. The latter investigated short pulse limit femtosecond laser pulses, where ionization can be thought of an instantaneous process. In this contribution, we demonstrate that multiphoton still observed when using...
Strong-field coherent control deals with the efficient excitation of a quantum system into preselected final state. In order to understand underlying mechanisms, transient dynamics laser-dressed states need be considered in addition. this paper, we present route towards complete picture non-perturbative control. To end, study near-resonant chirped potassium atoms as model for resonant strong-field Combining two-colour pump–probe scheme photoelectron spectroscopy, simultaneously observe state...
We investigate photoelectron circular dichroism (PECD) with coherent light sources whose pulse durations range from femtoseconds to nanoseconds. To that end, we employed an optical parametric amplifier, ultraviolet shaper, and a nanosecond dye laser, all centered around wavelength of 380 nm. A multiphoton ionization experiment on the gas-phase chiral prototype fenchone found PECD measured via 3s intermediate resonance is about 15% robust over five orders magnitude duration. remains despite...
Quantum chemical calculations of one-photon absorption, electronic circular dichroism and anisotropy factor spectra for the A-band transition fenchone, camphor 3-methylcyclopentanone (3MCP) are reported. While only weakly allowed nature leads to comparatively large anisotropies, a proper theoretical description absorption such requires account non-Condon effects. We present experimental data 3MCP in liquid phase show that corresponding Herzberg-Teller corrections critical reproduce main...
We demonstrate how the fast electron dynamics in molecules and hence reaction of system can be efficiently manipulated by controlling temporal phase an ultrashort laser pulse with attosecond precision.
We investigate how optimal control theory can be used to improve Circular Dichroism (CD) signals for the A-band of fenchone measured via photoionization yield upon further excitation. These transitions are electric dipole forbidden first order, which translates into low population transfer excited state but allows a clearer interplay between and magnetic transition moments, same order magnitude. Using model including electronic ground A as well all permanent multipole moments up quadrupole,...
We highlight the effect of nuclear motion on control scheme and in particular oscillating dipole.
Temporally delayed, phase-locked coherent pairs of near IR femtosecond laser pulses were employed to study electronic coherences in molecular Nd3+ -complexes at room temperature. Dissolved and solid complexes studied under a confocal microscope set-up with fluorescence detection. The observed coherence on few hundred femtoseconds time scale is modulated by additional wave packet dynamics, which we attribute mainly be vibrational nature. In future, the may serve as prototypes for possible...
The Cover Feature illustrates the creation and probing of a long-lived electronic coherence in molecular Nd-complexes by IR femtosecond laser pulses. is observed via Δτ-dependent modulation fluorescence signal shows influence additional vibrational dynamics. may serve as prototypes for possible future applications quantum information technology. More can be found Research Article Hendrike Braun co-workers.