A5003659857- Advanced Chemical Physics Studies
- Photochemistry and Electron Transfer Studies
- Molecular Spectroscopy and Structure
- Spectroscopy and Quantum Chemical Studies
- Spectroscopy and Laser Applications
- Atmospheric Ozone and Climate
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Molecular spectroscopy and chirality
- Mass Spectrometry Techniques and Applications
- Spectroscopy Techniques in Biomedical and Chemical Research
- Molecular Junctions and Nanostructures
- Magnetic and transport properties of perovskites and related materials
- Analytical Chemistry and Chromatography
- Porphyrin and Phthalocyanine Chemistry
- High-pressure geophysics and materials
- Nonlinear Optical Materials Research
- Spectroscopy and Chemometric Analyses
- Electronic and Structural Properties of Oxides
- Boron and Carbon Nanomaterials Research
- Free Radicals and Antioxidants
- Solid-state spectroscopy and crystallography
- Crystallography and molecular interactions
- Diamond and Carbon-based Materials Research
- Multiferroics and related materials
Heinrich Heine University Düsseldorf
2016-2025
University of Liège
2017-2025
Center for Theoretical Physics
2025
Heidelberg University
1991-2023
Friedrich Schiller University Jena
2016-2022
University Hospital Heidelberg
2022
Leibniz Institute of Photonic Technology
2009-2022
John Wiley & Sons (Germany)
2022
Technical University of Denmark
2022
Munster Technological University
2022
The S1←S0 000 transitions of phenol and the hydrogen bonded phenol(H2O)1 cluster have been studied by high resolution fluorescence excitation spectroscopy. All lines in monomer spectrum are split 56±4 MHz due to internal rotation −OH group about a axis. barrier for this motion is determined ground excited states; V2″=1215 cm−1, V2′=4710 cm−1. rotational constants state agreement with those reported microwave studies. were found be A′=5313.7 MHz, B′=2620.5 C′=1756.08 MHz. region redshifted...
Abstract This paper describes an automated assignment and fitting procedure for high-resolution rotationally resolved spectra. The method is based on the application of genetic algorithms (GA) both frequency intensity information these spectra used. basic ideas behind GA technique introduced particular fitness function critical success evaluation discussed. meta-optimization internal parameters optimal exploration error landscape spectrum investigated. A number typical examples are given in...
The properties of the three lowest singlet electronic states (ground, 1Lb, and 1La states) indole (C8H7N) have been calculated with second-order approximate coupled-cluster theory (CC2) within resolution-of-the-identity approximation. Refined energies at CC2 optimized structures transition dipole moments were using a density functional multi-reference configuration-interaction (DFT/MRCI) approach. Structures, energies, are reported for all compared to experimental values. From moments, we...
The microwave spectrum of phenol(H2O) has been recorded using a pulsed molecular beam Fourier transform spectrometer. Twenty a-type transitions have observed and assigned. All are doublets with splittings varying from 1.13 to 4.01 MHz. These interpreted result the internal rotation water molecule. ground state this torsional motion is split into two levels different spin statistical weights. Both treated independently as asymmetric rotor states. resulting rotational constants A=4291.486 MHz,...
The change in the geometry of 1,3-dicyanobenzene upon electronic excitation to lowest excited singlet state has been elucidated by simultaneous Franck–Condon (FC) fits fluorescence emission spectra originating from vibrationless origin and four vibronic bands. changes obtained FC were compared results ab initio calculations at SCS-CC2/cc-pVTZ level theory. We found close agreement between spectral determination theoretical prediction excitation. aromatic ring opens excitation, resulting a...
The atomic configuration of phases and their interfaces is fundamental to materials design engineering. Here, we unveil a transition metal oxide interface, whose formation driven by energetic influences─epitaxial tensile strain versus oxygen octahedra connectivity─that compete in determining the orientation an orthorhombic perovskite film. We study this phenomenon layers LaVO3 grown on (101) DyScO3, using atomic-resolution scanning transmission electron microscopy measure intrinsic markers...
The intermolecular vibrations of jet-cooled phenol(H2O)2-5 and phenol(D2O)2-5-d1 were investigated in the S0 S1 electronic states by using mass-selective UV spectral hole burning (SHB) single vibronic level dispersed fluorescence (DF) spectroscopy. Phenol(H2O)2 shows broad bands with congested structure. We succeeded obtaining its via double-resonance Previous studies phenol(H2O)3 completed. By employing soft two-color ionization burning, spectra phenol(H2O)4 phenol(H2O)5 unambiguously...
Combining density-functional perturbation theory with the frozen-phonon approach, anharmonic shift of Raman frequency covalent semiconductors diamond and silicon are determined ab initio. The temperature dependence contribution zero-point motion calculated as well linewidth. Corresponding results for germanium have been obtained assumption that quartic force constants may be approximated by those silicon.
Rotationally resolved electronic spectroscopy yields a wealth of information on molecular structures in different states. Unfortunately, for large molecules the spectra get rapidly very congested owing to close-lying vibronic bands, other isotopomers with similar zero-point energy shifts, or large-amplitude internal motions. A straightforward assignment single rovibronic lines and, therefore, line position assigned fits are impossible. An alternative approach is unassigned using genetic...
The conformational space of tryptamine has been thoroughly investigated using rotationally resolved laser-induced fluorescence spectroscopy. Six conformers could be identified on the basis inertial parameters several deuterated isotopomers. Upon attaching a single water molecule, collapses into conformer. For hydrogen-bonded cluster, this conformer is unambiguously as A. In complex, molecule acts proton donor with respect to amino group. An additional interaction one aromatic C-H bonds...
High-resolution electronic spectra of indole (C8H7N) and their detailed analysis are reported. Thirteen low-lying vibronic bands—from the origin transition at 35231.4 cm−1 up to 1000 above—are recorded with rotational resolution. Besides inertial parameters defects these yield information, for each individual band, on transition-dipole-moment orientations in molecular frame as well reorientation that upon excitation. The natural lifetimes states have also been determined. Strongly varying...
Spin-polarized electron-energy-loss spectroscopy was applied to study electron-exchange processes in insulating NiO(100). Dipole-forbidden d-d excitations of the ${\mathrm{Ni}}^{2+}$ ion give rise sharp gap structures energy-loss spectrum. Our measurements show strong spin-flip scattering with 1.1- and 1.6-eV energy loss up high primary electron energies more than 100 eV. No exchange is found leading structure around 2.8
p-cresol and its complexes with H2O CH3OH were cooled in a pulsed supersonic free jet studied by resonant multiphoton ionization time-of-flight mass analysis. Detailed concentration analysis allowed an unambiguous assignment of cluster size. The electronic origins (H2O)1,2,3 show irregular red- blueshifts change size, which is referred to the bivalent role as proton donor acceptor. Ab initio semiempirical quantum chemical calculations support this interpretation spectral shifts be...
Five different isotopologues of the benzoic acid dimer and a vibronic band located 57 cm(-1) above electronic origin, which is assigned to out-of-plane butterfly motion, are studied by rotationally resolved UV spectroscopy. From these measurements ground-state structure with C(2h) symmetry deduced, whereas lowered C(s) in S(1) state. The increase center-of-mass distance between two monomers that found on excitation indicates decrease hydrogen-bond strength. tunneling splittings S(0) states...
The structure and electronic properties of the ground lowest excited singlet states 5-cyanoindole (5CI) were determined using rotationally resolved spectroscopy vibrationless origin 5CI. In contrast to most other indole derivatives, state 5CI is be La character. conventional approximate coupled cluster singles doubles model (CC2) fails describe geometry correctly. Nevertheless, scaling spin components equal opposite spins within CC2 as proposed by Hellweg et al. (Phys. Chem. Phys., 2008, 10,...
The rotationally resolved electronic spectrum of 4-cyanoindole and some N-D C-D deuterated isotopologues has been measured analyzed. Dipole moments in the ground electronically excited state have determined, using Stark spectroscopy. From geometry changes upon excitation, orientation transition dipole moment, values for permanent moments, lowest singlet could be shown to La symmetry. lifetime isolated determined 11 ns, while ringdeuterated lifetimes between 5 6 ns found. different behavior...
The intermolecular vibrations of phenol–water and their tunneling (torsional) splittings have been assigned in the S1 state by mass resolved spectral hole burning. abundance transitions low frequency region spectra can be traced back to torsional water moiety, which splits all vibronic levels. Especially plane wag vibration β2 exhibits a large splitting points strong coupling with H2O torsion τ substantial lowering effective barrier after excitation. Based on discrimination different...
The phenol-ammonia 1:1 complex has been investigated by mass resolved hole burning spectroscopy and ab initio methods at the HF/6-31G(d,p) HF/6-31++G(d,p) levels of theory. By means spectral four bands in region intermolecular vibrations could be assigned to complex. computed cluster structure its normal are reported compared experimental results. Anharmonic calculations were carried out for ammonia torsion. results structurally related complexes.
Inter- and intramolecular vibrations of the Phenol dimer have been examined using spectral hole burning dispersed fluorescence spectroscopy. The spectra recorded via excitation electronic donor origin all intermolecular vibrational transitions. Franck–Condon intensity pattern allowed a straightforward assignment ground state frequencies to excited frequencies, which were by hole-burning existence another conformer that possibly absorbs in region interest was ruled out For obtaining spectra,...
Hole-burning spectra of 2H-benzotriazole and 2D-benzotriazole have been recorded in a range 1250 cm-1 above the electronic origin to rule out possibility that other tautomer (1H-benzotriazole) absorbs this frequency range. After establishing existence only one absorbing species by spectral hole-burning spectroscopy, dispersed fluorescence taken through several low-frequency vibronic bands 2H(2D)-benzotriazole recorded. The ground-state vibrational frequencies are compared results an ab...
The structures of the van der Waals bonded complexes phenol with one and two argon atoms have been determined using rotationally resolved electronic spectroscopy S1←S0 transition. experimentally structural parameters were compared to results quantum chemical calculations that are capable properly describing dispersive interactions in clusters. It was found both π-bound configurations, phenol-Ar2 complex adopting a symmetric (1∣1) structure. distances aromatic plane ground state n=1 n=2...