نتایج جستجو برای: raman sepectroscopy
تعداد نتایج: 35918 فیلتر نتایج به سال:
The influence of the electrode potential on the electronic structure of individual single-walled carbon nanotubes is studied using Raman spectroscopy. By analyzing the radial breathing mode intensity versus electrode potential profiles in the Raman spectra at many different laser excitation energies, we show that the charging of individual carbon nanotubes causes a broadening of the resonant Ra...
Strong Raman scattering is observed from iodine anions adsorbed at ca. 3% coverage on single layer graphene. In addition, the Raman signal from just one bromine intercalation layer inside three and four layer thick graphenes is observed. We analyze and model the intramolecular electronic, charge-transfer, and multiple reflection electromagnetic mechanisms responsible for this unusual sensitivit...
In this report we address the problem of skin fluorescence in feature extraction from Raman spectra of skin lesions. We apply a highly automated neural network method for suppressing skin fluorescence from Raman spectrum of skin lesions before dimension reduction with principal components analysis. By applying the background suppression, the effect of outlier spectrum in the principal component...
Resonance Raman spectra of the ferrous CO complex of cytochrome P-450cam have been observed both in its camphor-bound and free states. Upon excitation at 457.9 nm, near the absorption maximum of the Soret band, the ferrous CO complex of the camphor-bound enzyme showed an anomalously intense Raman line at 481 cm-1 besides the strong Raman lines at 1366 and 674 cm-1 for the porphyrin vibrations. ...
We present a method for robust timekeeping in which alkali-metal atoms are interrogated in a Ramsey sequence based on stimulated Raman transitions with optical photons. To suppress systematic effects introduced by differential ac Stark shifts and optical intensity gradients, we employ atom optics derived from Raman adiabatic rapid passage (ARP). Raman ARP drives coherent transfer between the al...
Raman spectroscopy reveals chemically specific information and provides label-free insight into the molecular world. However, the signals are intrinsically weak and call for enhancement techniques. Here, we demonstrate Purcell enhancement of Raman scattering in a tunable high-finesse microcavity, and utilize it for molecular diagnostics by combined Raman and absorption imaging. Studying individ...
Raman scattering is a potentially important probe of structure, dynamics, and thermal properties of single-molecule conduction junctions. We combine a nonequilibrium Green's function description of the junction with a generalized scattering theory of the Raman process, which provides the first theoretical description of Raman scattering from such systems. The voltage dependence of the Raman flu...
In this work, we utilize a short-wavelength, 532-nm picosecond pulsed laser coupled with a time-gated complementary metal-oxide semiconductor (CMOS) single-photon avalanche diode (SPAD) detector to acquire Raman spectra of several drugs of interest. With this approach, we are able to reveal previously unseen Raman features and suppress the fluorescence background of these drugs. Compared to tra...
The excitation energy-dependent nature of Raman scattering spectrum, vibration, electronic or both, has been studied using different excitation sources on as-grown and annealed n- and p-type modulation-doped Ga1 - xInxNyAs1 - y/GaAs quantum well structures. The samples were grown by molecular beam technique with different N concentrations (y = 0%, 0.9%, 1.2%, 1.7%) at the same In concentration...
The current study assessed the feasibility of the application of Raman spectroscopy toward the diagnosis of gout and pseudogout. First, the lowest concentrations of monosodium urate monohydrate (MSUM) and calcium pyrophosphate dihydrate (CPPD) crystals detectable by Raman spectroscopy were investigated by mixing known amounts of synthetic crystals with synovial fluid in the concentration range ...
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