C(60).C(8)H(8) and C(70).C(8)H(8) are prototypes of rotor-stator cocrystals. We present infrared and Raman spectra of these materials and show how the rotor-stator nature is reflected in their vibrational properties. We measured the vibrational spectra of the polymer phases poly(C(60)C(8)H(8)) and poly(C(70)C(8)H(8)) resulting from a solid-state reaction occurring on heating. On the basis of the spectra, we propose a connection pattern for the fullerene in poly(C(60)C(8)H(8)), where the symmetry of the C(60) molecule is D(2h). On illuminating the C(60).C(8)H(8) cocrystal with green or blue light, a photochemical reaction was observed leading to a product similar to that of the thermal polymerization.
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http://dx.doi.org/10.1021/jp075204h | DOI Listing |
We demonstrate a (FMCW) light detection and ranging (LIDAR) system utilizing a (SNSPD) to measure vibrational spectra using reflected signals at the single-photon level. By determining the time-variant Doppler shift of the reflected probe signal, this system successfully reconstructs various audio signals, including pure sinusoidal, multi-tonal, and musical signals, up to 200 Hz, limited by the laser frequency modulation rate and the Nyquist sampling theorem. Additionally, we employ scanning galvo mirrors to perform 3D measurements and map audio signals from different regions in the scanned field of view.
View Article and Find Full Text PDFSci Rep
January 2025
Institute of Noise and Vibration, Naval University of Engineering, Wuhan, 430033, China.
To suppress the significant vibration line spectra of piping systems under multi-frequency harmonic excitations, a novel dynamic vibration absorber (NDVA) is designed. The NDVA integrates numerous independent resonant units within a finite space through an ingenious structural design and possesses rich frequency regulation characteristics. A vibration model of the piping system equipped with the NDVA is established, and the approximate equivalent parameters of both the piping and the resonant units are inverted based on the frequency response function (FRF) test results.
View Article and Find Full Text PDFJ Chem Phys
January 2025
School of Chemistry, University of St Andrews, North Haugh, Fife, St Andrews KY16 9ST, United Kingdom.
Two synchrotron-based studies on 4H-pyran-4-thione, photoelectron spectroscopy and vacuum ultraviolet (VUV) absorption spectra were performed. A highly resolved structure was observed in the photoelectron spectrum (PES), in contrast to an earlier PES study, where little structure was observed. The sequence of ionic states was determined using configuration interaction and coupled cluster methods.
View Article and Find Full Text PDFHeliyon
January 2025
Universidade Estadual Paulista (Unesp), Instituto de Ciência e Tecnologia, Câmpus de São José dos Campos, São Paulo, Brazil.
Objective: This study aims to analyze saliva composition in crack users using vibrational spectroscopy.
Material And Methods: A total of 90 participants were meticulously selected and divided into three groups, each comprising 30 individuals. All participants met the criterion of having no observable clinical changes in the oral mucosa.
Spectrochim Acta A Mol Biomol Spectrosc
January 2025
Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø, DK-2100, Denmark. Electronic address:
We have recorded the gas phase spectrum of isoprene at room temperature from the mid-infrared range and into the visible range (600 cm to 17050 cm). Absorption spectra were obtained by Fourier transform infrared, conventional dispersion ultraviolet-visible-near-infrared and cavity ring-down spectroscopy to cover the entire range with a resolution comparable to that of the instruments on the James Webb Space Telescope. We have assigned the CH-stretching fundamental and overtone bands corresponding to the Δv=1-6 transitions based on anharmonic vibrational calculations using normal mode and local mode models, for the lower- and higher-energy regions, respectively.
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