Resonance Raman Spectroscopy Research Papers (original) (raw)

Citation: Mahfuzur Rahman M, et al. (2014) Nanoplasmonics and its Applied Devices. J Nanotech Smart Mater 1: 1-15 Abstract Nanoplasmonics makes a connection to conventional optics to the nanoworld. Interesting performance like... more

Citation: Mahfuzur Rahman M, et al. (2014) Nanoplasmonics and its Applied Devices. J Nanotech Smart Mater 1: 1-15 Abstract Nanoplasmonics makes a connection to conventional optics to the nanoworld. Interesting performance like subwave-length focusing to invisibility cloaking, nanoplasmonics have profound applications in science and engineering world from biophotonics to nanocircuitry. Metal and dielectric have free d-shell electrons. When metal and dielectric of different refrac-tive index come in contact, these free electrons get accumulated in a region at the metal-semiconductor interface forming nanoplasmons. Practical implementation of nano device fabrication is the most challenging task due to the dissipative losses in metal. The optimum operating condition can be achieved by the efficient use of optical gain. We review here the ongoing progress in the field of nanoplasmonic research.

The scope of this work is to provide you with an overview of the chemical physics of resonance Raman spectroscopy, present and discuss some examples of resonance Raman spectra, and discuss those things to be alert to in recognizing... more

The scope of this work is to provide you with an overview of the chemical physics of resonance Raman spectroscopy, present and discuss some examples of resonance Raman spectra, and discuss those things to be alert to in recognizing resonance enhancement in your Raman spectra. How does resonance Raman spectroscopy differ from so-called normal Raman spectroscopy? The primary difference is that the scattering strength of those Raman active vibrational modes associated with the electronic transition are greatly enhanced, up to 106 times the signal strength observed when performing normal Raman spectroscopy. The presence of bands attributable to second order overtone and combination modes in resonance Raman spectra is explained.

Resonance Raman spectra of oxygenated and deoxygenated functional erythrocytes recorded using 785 nm laser excitation are presented. The high-quality spectra show a mixture of enhanced A1g, A2g, B1g, B2g, Eu and vinyl modes. The high... more

Resonance Raman spectra of oxygenated and deoxygenated functional erythrocytes recorded using 785 nm laser excitation are presented. The high-quality spectra show a mixture of enhanced A1g, A2g, B1g, B2g, Eu and vinyl modes. The high sensitivity of the Raman system enabled spectra from four oxygenation and deoxygenation cycles to be recorded with only 18 mW of power at the sample over a 60-minute period. This low power prevented photo-/thermal degradation and negated protein denaturation leading to heme aggregation. The large database consisting of 210 spectra from the four cycles was analyzed with principal components analysis (PCA). The PC1 loadings plot provided exquisite detail on bands associated with the oxygenated and deoxygenated states. The enhancement of a band at 567 cm−1, observed in the spectra of oxygenated cells and the corresponding PC1 loadings plot, was assigned to the Fe–O2 stretching mode, while a band appearing at 419 cm−1 was assigned to the Fe–O–O bending mode based on previous studies. For deoxygenated cells, the enhancement of B1g modes at 785 nm excitation is consistent with vibronic coupling between band III and the Soret transition. In the case of oxygenated cells, the enhancement of iron-axial out-of-plane modes and non-totally symmetric modes is consistent with enhancement into the y,z-polarized transition {\text{a}}_{{{\text{iu}}}} {\left( {\text{ $ \pi $ }} \right)} \to {\text{d}}_{{{\text{xz}}}} + {\text{O}}_{{\text{2}}} {\left( {{\text{ $ \pi $ }}_{{\text{g}}} } \right)}$$ centered at 785 nm. The enhancement of non-totally symmetric B1g modes in oxygenated cells suggests vibronic coupling between band IV and the Soret band. This study provides new insights into the vibrational dynamics, electronic structure and resonant enhancement of heme moieties within functional erythrocytes at near-IR excitation wavelengths.

Resonant Raman scattering is highly desired for material study. It is experimentally not easy to reach the resonant scattering interaction between an incident photon and a material due to the limited available laser wavelengths. In this... more

Resonant Raman scattering is highly desired for material study. It is experimentally not easy to reach the resonant scattering interaction between an incident photon and a material due to the limited available laser wavelengths. In this study, by employing silver plasmonic nanoparticles deposited on glass substrate and by in situ adjusting the cadmium sulfide (CdS) band gap through heat treatment, resonant Raman scattering condition (laser wavelength of 514.5 nm) was fully achieved in nanocrystalline CdS thin films. The dramatically enhanced Raman scattering allowed us to in situ monitor the phase transition that occurred during the heat treatment and to quantitatively characterize the fraction of the zincblende (cubic) CdS in the main base of wurtzite (hexagonal) CdS. Raman multi-phonon and the corresponding high-order scattering modes were observed due to the much enhanced surface nanoplasmonic electric field.

Channelrhodopsin-2 mediates phototaxis in green algae by acting as a light-gated cation channel. As a result of this property, it is used as a novel optogenetic tool in neurophysiological applications. Structural information is still... more

Channelrhodopsin-2 mediates phototaxis in green algae by acting as a light-gated cation channel. As a result of this property, it is used as a novel optogenetic tool in neurophysiological applications. Structural information is still scant and we present here the first resonance Raman spectra of channelrhodopsin-2. Spectra of detergent solubilized and lipid-reconstituted protein were recorded under pre-resonant conditions to exclusively probe retinal in its electronic ground state. All-trans retinal was identified to be the favoured configuration of the chromophore but significant contributions of 13-cis were detected. Pre-illumination hardly changed the isomeric composition but small amounts of presumably 9-cis retinal were found in the light-adapted state. Spectral analysis suggested that the Schiff base proton is strongly hydrogen-bonded to a nearby water molecule.