We present a theoretical investigation of the Goös-Hanchen shift (GHS) experienced by acoustic and optical vibrational modes reflected and transmitted from the surfaces of a semiconductor thin film sandwiched between two semi-infinite media. Our study focuses on the impact of the incident angle on the GHS, considering the coupling between longitudinal and transverse modes. For acoustic vibrations, our findings reveal that the GHS can reach magnitudes up to seven times larger than the thickness of the thin film and up to 20 times larger than the incident wavelength. Besides, it is shown that this significant amplification of the GHS highlights the strong influence of the incident angle and the frequency of the modes involved. In the case of optical vibrations, we observe even more pronounced GHS values, exceeding 30 times the incident wavelength. This demonstrates the potential of GHS in acoustical systems, which opens up possibilities for applications in the design of acoustic devices.
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http://dx.doi.org/10.1088/1361-648X/ad3370 | DOI Listing |
J Phys Chem A
January 2025
Department of Chemistry and Chemical Sciences, Central University Jammu, Samba 181143, Jammu and Kashmir, India.
The development of accurate yet fast quantum mechanical methods to calculate the anharmonic vibrational spectra of large molecules is one of the major goals of ongoing developments in this field. This study extensively explores and validates a hybrid electronic basis set approach for anharmonic vibrational calculations, where the molecule is segregated into different computational layers, and such layers are then treated with different levels of electronic basis sets. Following the system-bath model, the atoms corresponding to the active sites are treated in more accurate but computationally slower, large basis set and the rest of the atoms in less accurate but computationally faster, small basis set to construct the anharmonic hybrid potential energy surface (PES).
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Novosibirsk State University, Pirogov str. 1, Novosibirsk 630090, Russian Federation.
Nine metal complexes formed by three symmetric β-diketonates (, acetylacetonate (), 1,1,1,3,3,3-hexafluoro-acetylacetonate (), and 2,2,6,6-tetramethylheptane-3,5-dionate ()) and three metal ions (with three different coordination geometries, , Be - tetrahedral, Cu - square planar, and Pb - "swing" square pyramidal) were investigated. The study combines structural analyses, vibrational spectroscopic techniques, and quantum chemical calculations with the aim of bridging crystal structure, electronic structure, molecular topology, and far-infrared (FIR) spectroscopic characteristics. The effect of intramolecular interactions on the structural, electronic, and spectroscopic features is the center of this study.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2025
Department of Physics, Deshbandhu College (University of Delhi), New Delhi 110019, India.
The analysis of Raman and Infrared (IR) phonons in monolayered tetragonal (Sr, Ba)HfO compounds, which exhibit D symmetry and belong to the I4/mmm phase of space group 139 with Z = 2, has been conducted using normal coordinates. The SrHfO and BaHfO compounds are the first members of the Ruddlesden-Popper (RP) series denoted as (Sr, Ba)HfO with n = 1. Nine Short-Range Force Constants (SRFC) have been included in theoretical calculations to analyze the optical phonons of SrHfO and BaHfO compounds within the I4/mmm phase.
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 PDFNat Chem
January 2025
Department of Chemistry, University of California Irvine, Irvine, CA, USA.
Controlling reaction outcomes through external influences is a central goal in chemistry. Vibrational coupling between molecular vibrations and cavity modes is rapidly emerging as a distinct strategy compared with conventional thermochemical and photochemical methods; however, insight into the fundamental mechanisms remains limited. Here we investigate how vibrational weak and strong coupling in plasmonic nanocavities modifies the thermal dehydration of copper sulfate pentahydrate.
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