Ultrafast table-top X-ray spectroscopy at the carbon K-edge is used to measure the X-ray spectral features of benzene radical cations (Bz). The ground state of the cation is prepared selectively by two-photon ionization of neutral benzene, and the X-ray spectra are probed at early times after the ionization by transient absorption using X-rays produced by high harmonic generation (HHG). Bz is well-known to undergo Jahn-Teller distortion, leading to a lower symmetry and splitting of the π orbitals. Comparison of the X-ray absorption spectra of the neutral and the cation reveals a splitting of the two degenerate π* orbitals as well as an appearance of a new peak due to excitation to the partially occupied π-subshell. The π* orbital splitting of the cation, elucidated on the basis of high-level calculations in a companion theoretical paper [Vidal et al. http://dx.doi.org/10.1021/acs.jpca.0c08732], is discovered to be due to both the symmetry distortion and even more dominant spin coupling of the unpaired electron in the partially vacant π orbital (from ionization) with the unpaired electrons resulting from the transition from the 1s core orbital to the fully vacant π* orbitals.
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http://dx.doi.org/10.1021/acs.jpca.0c08736 | DOI Listing |
Rev Sci Instrum
October 2024
Faculty of Physics and Center for Nanointegration (CENIDE), University of Duisburg-Essen, Lotharstrasse 1, 47057 Duisburg, Germany.
We present a table-top setup for x-ray absorption spectroscopy (XAS) based on high harmonic generation (HHG) in noble gases. Using sub-millijoule pump pulses at a central wavelength of 1550 nm, broadband HHG in the range of 70-350 eV was demonstrated. The HHG coherence lengths of several millimeters were achieved by reaching the nonadiabatic regime of harmonic generation.
View Article and Find Full Text PDFRev Sci Instrum
July 2024
State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China.
Vet Rec
July 2024
Private practitioner, Storrington, UK.
Background: Focused ultrasonographic imaging techniques are commonly used for cats and dogs; however, such techniques have not been described in rabbits.
Methods: Focused abdominal ultrasonography was performed on 12 healthy conscious rabbits using four acoustic windows: xiphisternal, left and right renal and cystic. They were positioned in sternal recumbency on a table top, with a cut-out area to allow access to the ventral abdomen.
Chem Rev
May 2024
Molecular Biophysics & Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States.
Utilization of renewable energies for catalytically generating value-added chemicals is highly desirable in this era of rising energy demands and climate change impacts. Artificial photosynthetic systems or photocatalysts utilize light to convert abundant CO, HO, and O to fuels, such as carbohydrates and hydrogen, thus converting light energy to storable chemical resources. The emergence of intense X-ray pulses from synchrotrons, ultrafast X-ray pulses from X-ray free electron lasers, and table-top laser-driven sources over the past decades opens new frontiers in deciphering photoinduced catalytic reaction mechanisms on the multiple temporal and spatial scales.
View Article and Find Full Text PDFNat Commun
February 2024
RIKEN SPring-8 Center, 1-1-1 Koto, Sayo, Sayo District, Hyogo, 679-5148, Japan.
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