Harmonium is a vacuum ultraviolet (VUV) photon source built within the Lausanne Centre for Ultrafast Science (LACUS). Utilising high harmonic generation, photons from 20-110 eV are available to conduct steady-state or ultrafast photoelectron and photoion spectroscopies (PES and PIS). A pulse preserving monochromator provides either high energy resolution (70 meV) or high temporal resolution (40 fs). Three endstations have been commissioned for: a) PES of liquids; b) angular resolved PES (ARPES) of solids and; c) coincidence PES and PIS of gas phase molecules or clusters. The source has several key advantages: high repetition rate (up to 15 kHz) and high photon flux (1011 photons per second at 38 eV). The capabilities of the facility complement the Swiss ultrafast and X-ray community (SwissFEL, SLS, NCCR MUST, etc.) helping to maintain Switzerland's leading role in ultrafast science in the world.
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http://dx.doi.org/10.2533/chimia.2017.268 | DOI Listing |
Se Pu
February 2025
CAS Key Laboratory of Separation Sciences for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Chemical modifications are widely used in research fields such as quantitative proteomics and interaction analyses. Chemical-modification targets can be roughly divided into four categories, including those that integrate isotope labels for quantification purposes, probe the structures of proteins through covalent labeling or cross-linking, incorporate labels to improve the ionization or dissociation of characteristic peptides in complex mixtures, and affinity-enrich various poorly abundant protein translational modifications (PTMs). A chemical modification reaction needs to be simple and efficient for use in proteomics analysis, and should be performed without any complicated process for preparing the labeling reagent.
View Article and Find Full Text PDFAnal Chem
January 2025
Key Laboratory of Green Chemistry & Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan610064, China.
It is still challenging to perform a high-throughput digestion on limited amounts of sample prior to elemental analysis by atomic spectrometry. Herein, a photochemical reactor consisting of a quartz tube inserted into a low-pressure mercury lamp was used to fabricate a flow droplet photodigestion (FD-PD) device for the high-throughput digestion of small amounts of samples. A mixture containing 20 μL of blood sample, 20 μL of HO, and 10 μL of HNO was pumped and passed through the reactor before its online analysis by hydride generation atomic fluorescence spectrometry (HG-AFS).
View Article and Find Full Text PDFJ Chem Phys
January 2025
School of Chemistry, University of St Andrews, North Haugh, Fife, St Andrews KY16 9ST, United Kingdom.
Two synchrotron-based studies on 4H-pyran-4-thione, photoelectron spectroscopy and vacuum ultraviolet (VUV) absorption spectra were performed. A highly resolved structure was observed in the photoelectron spectrum (PES), in contrast to an earlier PES study, where little structure was observed. The sequence of ionic states was determined using configuration interaction and coupled cluster methods.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
Despite major progress in the investigation of boron cluster anions, direct experimental study of neutral boron clusters remains a significant challenge because of the difficulty in size selection. Here we report a size-specific study of the neutral B cluster using threshold photoionization with a tunable vacuum ultraviolet free electron laser. The ionization potential of B is measured to be 8.
View Article and Find Full Text PDFJ Mol Model
January 2025
College of Electronics and Information, Xi'an Polytechnic University, Xian, People's Republic of China.
Context: The two-dimensional graphene/MoTe heterostructure holds extensive potential applications in optoelectronic devices, sensors, and catalysts. To expand its optical applications, this study systematically investigates the adsorption stability of metal atoms (Au, Pt, Pd, and Fe) on the graphene/MoTe and their influence on its optoelectronic properties employing first-principles methods. The findings indicate that after the adsorption of Au and Pd, the structure retains its direct bandgap properties, while the adsorption of Pt and Fe exhibits indirect bandgap characteristics.
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