Topic
Raman spectroscopy
About: Raman spectroscopy is a research topic. Over the lifetime, 122605 publications have been published within this topic receiving 2891083 citations. The topic is also known as: Raman Spectrum Analysis & spectrum Analysis, Raman.
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TL;DR: In this paper, the surface-enhanced Raman scattering (SERS) spectroscopy of anisotropic metallic nanoparticles (NPs) was investigated using 2-mercaptopyridine (2-MPy) and crystal violet probing molecules.
Abstract: Anisotropic metallic nanoparticles (NPs) have unique optical properties, which lend them to applications such as surface-enhanced Raman scattering (SERS) spectroscopy. Star-shaped gold (Au) NPs were prepared in aqueous solutions by the seed-mediated growth method and tested for Raman enhancement using 2-mercaptopyridine (2-MPy) and crystal violet (CV) probing molecules. For both molecules, the SERS activity of the nanostars was notably stronger than that of the spherical Au NPs of similar size. The Raman enhancement factors (EFs) for 2-MPy on Au nanostars and nanorods are comparable and estimated as greater than 5 orders of magnitude. However, the enhancement for CV on nanostars was significantly higher than for nanorods, in particular at CV concentrations of 100 nM or lower. This article is a US Government work and is in the public domain in the USA. Published in 2008 by John Wiley & Sons, Ltd.
272 citations
TL;DR: In this paper, the first successful attempt at synthesizing diamond by chemical vapor deposition with the use of a dc plasma jet was described, and the growth rate of the diamond film was 80 μm/h.
Abstract: This letter describes the first successful attempt at synthesizing diamond by chemical vapor deposition with the use of a dc plasma jet. A plasma jet, formed by the dc arc discharge of CH4 diluted with H2, was sprayed onto a water‐cooled substrate. The growth rate of the diamond film was 80 μm/h. The crystallinity measures well in terms of x‐ray diffraction and Raman spectroscopy. The quenching effect of the thermal plasma is discussed in relation to the high growth rate obtained.
272 citations
TL;DR: In this paper, the properties of the metaphosphate vibration in binary metal oxide glasses have been investigated and it has been shown that the vibrational frequency of the metal cation and the glass network is correlated with its mass, charge, and ionic radius.
Abstract: Thirty different binary metal oxide glasses having the metaphosphate composition have been prepared containing cations from the following groups: alkali metals, alkaline earths, transition metals, and lanthanide and actinide metals. Far infrared absorption assigned to the cation vibration in its oxygen cage has been measured for these glasses. Empirical ionic models are proposed correlating the absorption maximum with the cation mass, charge, and ionic radius. Discrepancies between the observed and predicted vibrational frequency indicate a more covalent interaction between the metal cation and the glass network. Raman intensities and vibrational frequencies of the network metaphosphate vibrations have been obtained and provide additional evidence about the cation–site interaction.
272 citations
TL;DR: In this article, a facile vapor diffusion method in combination with calcination at 550 °C was used to synthesize novel CoFe2O4 hollow sphere/graphene composites.
Abstract: Novel CoFe2O4 hollow sphere/graphene composites were synthesized by a facile vapor diffusion method in combination with calcination at 550 °C. The structure and morphology of as-prepared hybrid materials were characterized by electron microscopy, X-ray diffractometry, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Uniform CoFe2O4 hollow spheres with a diameter of about 500 nm and a shell thickness of approximately 50 nm were homogeneously distributed on graphene sheets. The electromagnetic parameters were measured using a vector network analyzer. A minimum reflection loss of −18.5 dB was observed at 12.9 GHz for the CoFe2O4 hollow sphere/graphene composites with a thickness of 2 mm, and the effective absorption frequency ranged from 11.3 to 15.0 GHz. The CoFe2O4 hollow sphere/graphene composites exhibited better microwave absorbing performance than the CoFe2O4 hollow spheres. A possible formation mechanism for CoFe2O4 hollow sphere/graphene composites was proposed.
272 citations
TL;DR: The individual resonance Raman spectra of the PM568 and M412 forms of light-adapted purple membrane from Halobacterium halobium have been measured and indicate that the retinal chromophore is linked to the purple membrane protein via a protonated and unprotonated Schiff base.
Abstract: The individual resonance Raman spectra of the PM568 and M412 forms of light-adapted purple membrane from Halobacterium halobium have been measured using the newly developed flow technique. For comparison purposes, the Raman spectra of the model chromophores, all-trans- and 13-cis retinal n-butylamine, both as protonated and unprotonated Schiff bases, have also been obtained. In agreement with previous work, the Raman data indicate that the retinal chromophore is linked to the purple membrane protein via a protonated. Schiff base in the case of the PM568 and an unprotonated Schiff base for the M412 form. The basic mechanism for color regulation in both forms appears to be electron delocalization. The spectral features of the two forms are different from each other and different from the model compound spectra.
271 citations