The existence of a mediating state for the ultrafast electronic relaxation in ethylenic-like molecules has been shown by femtosecond electron imaging techniques. This state is of Rydberg character, and its high efficiency is due to its ability to link the electron distributions of the initial and final electronic states.
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http://dx.doi.org/10.1021/ja052269u | DOI Listing |
J Phys Chem Lett
January 2025
Department of Chemistry, Virginia Commonwealth University, Richmond, Virginia 23284, United States.
Ethylene glycol dinitrate (EGDN) is a nitrate ester explosive widely used in military ordnance and missile systems. This study investigates the decomposition dynamics of the EGDN cation using a comprehensive approach that combines femtosecond time-resolved mass spectrometry (FTRMS) experiments with electronic structure and molecular dynamics computations. We identify three distinct dissociation time scales for the metastable EGDN cation of approximately 40-60 fs, 340-450 fs, and >2 ps.
View Article and Find Full Text PDFUltrasound Med Biol
January 2025
Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong; Biomedical Engineering Programme, The University of Hong Kong, Hong Kong. Electronic address:
Objective: Near-field (NF) clutter filters are critical for unveiling true myocardial structure and dynamics. Randomized singular value decomposition (rSVD) stands out for its proven computational efficiency and robustness. This study investigates the effect of rSVD-based NF clutter filtering on myocardial motion estimation.
View Article and Find Full Text PDFNanotechnology
January 2025
Walker Department of Mechanical Engineering, The University of Texas at Austin, 204 E. Dean Keeton St., Austin, Texas, 78712-1139, UNITED STATES.
Sapphire is an attractive material in photonic, optoelectronic, and transparent ceramic applications that stand to benefit from surface functionalization effects stemming from micro/nanostructures. Here we investigate the use of ultrafast lasers for fabricating nanostructures in sapphire by exploring the relationship between irradiation parameters, morphology change, and selective etching. In this approach an ultrafast laser pulse is focused on the sapphire substrate to change the crystalline morphology to amorphous or polycrystalline, which is characterized by examining different vibrational modes using Raman spectroscopy.
View Article and Find Full Text PDFAdv Mater
January 2025
Henry Royce Institute and Photon Science Institute, Department of Electrical and Electronic Engineering, The University of Manchester, Oxford Road, Manchester, M13 9PL, UK.
As human-machine interface hardware advances, better sensors are required to detect signals from different stimuli. Among numerous technologies, humidity sensors are critical for applications across different sectors, including environmental monitoring, food production, agriculture, and healthcare. Current humidity sensors rely on materials that absorb moisture, which can take some time to equilibrate with the surrounding environment, thus slowing their temporal response and limiting their applications.
View Article and Find Full Text PDFJ Phys Condens Matter
January 2025
ECE Department, University of Wisconsin at Madison, 1415 Engineering Dr, Rm 3442, Madison, WI 53706, USA, Madison, Wisconsin, 53706, UNITED STATES.
Two-dimensional (2D) van der Waals materials are shaping the landscape of next-generation devices, offering significant technological value thanks to their unique, tunable, and layer-dependent electronic and optoelectronic properties. Time-domain spectroscopic techniques at terahertz (THz) frequencies offer noninvasive, contact-free methods for characterizing the dynamics of carriers in 2D materials. They also pave the path toward the applications of 2D materials in detection, imaging, manufacturing, and communication within the increasingly important THz frequency range.
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