Atomic emission spectra provide a means to identify and to gain insight into the electronic structure of emitting or absorbing matter. Detailed procedures are provided for the construction of low-pressure electrodeless discharge lamps that yield targeted emission in the vacuum ultraviolet for the spectroscopic study of water vapor and halogen species aboard an array of airborne observation platforms in the upper atmosphere, as well as in laboratory environments. While specific to the production of Lyman-alpha, atomic chlorine, and atomic bromine emissions in this study, the configuration of the lamps and their interchangeability with respect to operation lend these procedures to constructing sources engaging a wide selection of atomic and molecular spectra with straightforward modifications. The features and limitations of each type of lamp are discussed, as well as methods to improve spectral purity and factors affecting operational lifetime.
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http://dx.doi.org/10.1364/AO.520905 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Brown University, Department of Chemistry, UNITED STATES OF AMERICA.
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 B9 cluster using threshold photoionization with a tunable vacuum ultraviolet free electron laser. The ionization potential of B9 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.
View Article and Find Full Text PDFBMC Vet Res
January 2025
Department of Anesthesiology, West China Hospital, Sichuan University, Chengdu, China.
Background: Mixed exhaled air has been widely used to determine exhaled propofol concentrations with online analyzers, but changes in dead space proportions may lead to inaccurate assessments of critical drug concentration data. This study proposes a method to correct propofol concentration in mixed air by estimating pulmonary dead space through reconstructing volumetric capnography (Vcap) from time-CO and time-volume curves, validated with vacuum ultraviolet time-of-flight mass spectrometry (VUV-TOF MS).
Methods: Existing monitoring parameters, including time-volume and time-CO curves, were used to determine Vcap.
ACS Appl Mater Interfaces
January 2025
Laboratory of Organic Electronics, Department of Science and Technology (ITN), Linköping University, Norrköping SE-60174, Sweden.
Here, the Fermi level () shifts of several donor and acceptor materials in different atmospheres are systematically studied by following the work function (WF) changes with Kelvin probe measurements, ultraviolet photoelectron spectroscopy, and near-ambient pressure X-ray photoelectron spectroscopy. Reversible shifts are found with the trend of higher WFs measured in ambient air and lower WFs measured in high vacuum compared to the WFs measured in ultrahigh vacuum. The shifts are energy level and morphology-dependent, and two mechanisms are proposed: (1) competition between p-doping induced by O and HO/O complexes and n-doping induced by HO; (2) polar HO molecules preferentially modifying the ionization energy of one of the frontier molecular orbitals over the other.
View Article and Find Full Text PDFInorg Chem
January 2025
School of Physics and Materials Science, Changji University, Changji 831100, People's Republic of China.
Finding novel efficient nonlinear optical materials with large second-order nonlinearity for the UV spectral range remains a formidable challenge, especially for silicate systems. Using a high-temperature solid reaction in a tight vacuum environment, two ultraviolet nonlinear optical materials with a moderate second harmonic generation (SHG) response have been created: PbSiOC and PbCaSiO. The SHG values they computed are roughly 2.
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