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Combining ultrahigh sensitivity, spatial resolution, and the capability to resolve chemical information, tip-enhanced Raman spectroscopy (TERS) is a powerful tool to study molecules or nanoscale objects. Here we show that TERS can also be a powerful tool in studying two-dimensional materials. We have achieved a 10^{9} Raman signal enhancement and a 0.5 nm spatial resolution using monolayer silicene on Ag(111) as a prototypical 2D material system. Because of the selective enhancement on Raman modes with vertical vibrational components in TERS, our experiment provides direct evidence of the origination of Raman modes in silicene. Furthermore, the ultrahigh sensitivity of TERS allows us to identify different vibrational properties of silicene phases, which differ only in the bucking direction of the Si-Si bonds. Local vibrational features from defects and domain boundaries in silicene can also be identified.
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http://dx.doi.org/10.1103/PhysRevLett.119.196803 | DOI Listing |
Biosystems
September 2025
Department of Physics, Razi University, Kermanshah, Iran.
From a physics perspective, DNA and RNA molecules are characterized as dynamic biological structures that exhibit vibrations across a range of time scales. To conduct a more accurate investigation of their dynamic properties, it is essential to consider the environmental conditions surrounding these molecules. A harmonic Hamiltonian that incorporates damping, along with the Green's function method, has been utilized to analyze the vibrational responses of viscous DNA and RNA strands.
View Article and Find Full Text PDFJ Phys Chem A
September 2025
Department of Chemistry, Brown University, Providence, Rhode Island 02912, United States.
Chlorothiophenols are key precursors for polychlorinated dibenzothiophenes, which are a class of persistent organic pollutants environmentally, but little is known about their electronic and spectroscopic properties. We report a high-resolution spectroscopic investigation of the cryogenically cooled 2-chlorothiophenoxide (2-CTP) anion using photoelectron imaging, photodetachment spectroscopy, and resonant photoelectron spectroscopy. High-resolution photoelectron spectroscopy yields an accurate electron affinity of 21,005 ± 5 cm (2.
View Article and Find Full Text PDFPLoS One
September 2025
Computational Chemistry Laboratory, Chemistry Department, Faculty of Science, Minia University, Minia, Egypt.
Polar protic and aprotic solvents can effectively simulate the maturation of breast carcinoma cells. Herein, the influence of polar protic solvents (water and ethanol) and aprotic solvents (acetone and DMSO) on the properties of 3-(dimethylaminomethyl)-5-nitroindole (DAMNI) was investigated using density functional theory (DFT) computations. Thermodynamic parameters retrieved from the vibrational analysis indicated that the DAMNI's entropy, heat capacity, and enthalpy increased with rising temperature.
View Article and Find Full Text PDFChem Soc Rev
September 2025
State Key Laboratory of Crystal Materials, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
Understanding the excited-state dynamics of atomically precise coinage metal nanoclusters (CMNCs) is pivotal for elucidating their photoluminescence (PL) mechanisms and rationally tuning emission properties-particularly in the near-infrared (NIR) region, where CMNC-based nanomaterials have tremendous potential for biomedical and optoelectronic applications. This review presents a systematic and comprehensive account of recent advances in investigating the excited-state dynamics and PL mechanisms of NIR-emitting CMNCs with atomic precision, leveraging the synergistic integration of time-resolved spectroscopy and time-dependent density functional theory (TD-DFT) calculations. Distinct from previous reviews that offer a broad survey of CMNC properties, the present review focuses specifically on intrinsic factors, highlighting molecular vibrational features and electronic structure modulation as key determinants of NIR emission.
View Article and Find Full Text PDFJ Phys Chem Lett
September 2025
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, U.K.
The electron-deficient oxidant 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) has recently emerged as a promising visible-light photoredox catalyst. However, its excited-state behavior remains poorly understood. Here, we investigate the ultrafast dynamics of photoexcited DDQ in acetonitrile using transient electronic and infrared absorption spectroscopy, supported by quantum chemical calculations.
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