The photodissociation of CH2XCH2Y (X,Y=Br,Cl) through absorption of 193 nm photons was investigated using product translational spectroscopy. No stable CH2BrCH2 or CH2ClCH2 was detected. The recorded time-of-flight spectra indicate that these internally excited radicals dissociated into Y+C2H4 in a concerted reaction with the first C-X bond rupture. Product anisotropy implies that the overall reaction time for three-body formation is in a fraction of rotational period. According to an asynchronous concerted reaction model, the measured spectra were simulated with product translational energy distributions coupled by asymmetric angular distributions. For the mixed halide, CH2BrCH2Cl, triple products Br+Cl+C2H4 can be originated from the cleavage of either the C-Br bond or the C-Cl bond. The results are discussed and where appropriate, comparisons with previous investigations of the related molecules are included.
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http://dx.doi.org/10.1063/1.1633262 | DOI Listing |
Micromachines (Basel)
November 2024
College of Aeronautical Engineering, Civil Aviation University of China, Tianjin 300300, China.
To enhance the tribological properties of the coatings and to inhibit cracking, sandwich-structured composite coatings were fabricated, consisting of a Ni60CuMo/IN718 transition layer and a Ni60CuMo/Ni-coated Cu wear-resistant layer with four different Ni-coated Cu contents. The results indicate that the transition layer inhibits the crack formation in the coating, and the refined grain structure stabilizes its average hardness at approximately 485 HV. Increasing the Cu content in the wear-resistant layer exacerbates the segregation of the Cu-rich solid solution phases and refines the in situ-generated CrC, TiC, and NbC phases.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Department of Chemical Engineering, University of Massachusetts Amherst, Amherst, Massachusetts 01003, USA.
We have performed a data science study of Monte Carlo (MC) simulation trajectories to understand factors that can accelerate the formation of zeolite nanoporous crystals, a process that can take days or even weeks. In previous work, MC simulations predicted and experiments confirmed that using a secondary organic structure-directing agent (OSDA) accelerates the crystallization of all-silica LTA zeolite, with experiments finding a three-fold speedup [Bores et al., Phys.
View Article and Find Full Text PDFEBioMedicine
December 2024
Digestive Diseases and Microbiota Group, Girona Biomedical Research Institute (IDIBGI), 17190, Salt, Girona, Spain. Electronic address:
Ageing Res Rev
January 2025
Department of Molecular and Cellular Biology, College of Osteopathic Medicine, Sam Houston State University, 925 City Central Avenue, Conroe, Texas 77304, United States.
This is the third review in our series examining the connection between osteosarcopenic adiposity/obesity (OSA/OSO) syndrome and health impairments. The objective here was to examine whether there is a causal and/or bidirectional relationship between OSA and some chronic diseases. The search (in PubMed, Scopus, and WoS), screened for articles from their inception to the end of February 2024.
View Article and Find Full Text PDFJ Phys Chem Lett
November 2024
Sorbonne Université, CNRS, UMR 7614, Laboratoire de Chimie Physique-Matière et Rayonnement, F-75005 Paris, France.
In our work, we demonstrate that X-ray photons can initiate a "molecular catapult" effect, leading to the dissociation of chemical bonds and the formation of heavy fragments within just a few femtoseconds. We reconstruct the momenta of fragments from a three-body dissociation in bromochloromethane using the ion pair average (IPA) reference frame, demonstrating how light atomic groups, such as alkylene and alkanylene, can govern nuclear dynamics during the dissociation process, akin to projectiles released by a catapult. Supported by calculations, this work highlights the crucial role of low-reduced-mass vibrational modes in driving ultrafast chemical processes.
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