Shining Light on Growth-Dependent Surface Chemistry of Organic Crystals: A Polarized Raman Spectroscopic and Computational Study of Aspirin

2019 ◽  
Vol 19 (2) ◽  
pp. 1288-1298 ◽  
Author(s):  
Anuradha R. Pallipurath ◽  
Jonathan M. Skelton ◽  
Andrea Erxleben ◽  
Patrick McArdle
Keyword(s):  
Surface Chemistry ◽  
Computational Study ◽  
Organic Crystals ◽  
Raman Spectroscopic ◽  
Polarized Raman

Polarized Raman spectroscopic characterization of normal and oral cancer blood plasma

2017 ◽  
Author(s):  
Rekha Pachaiappan ◽  
Aruna Prakasarao ◽  
Ganesan Singaravelu
Keyword(s):  
Oral Cancer ◽  
Blood Plasma ◽  
Spectroscopic Characterization ◽  
Raman Spectroscopic ◽  
Polarized Raman

Surface Chemistry Modulates CO2 Reduction Reaction Intermediates on Silver Nanoparticle Electrocatalysts

2020 ◽  
Author(s):  
Tomos Harris ◽  
Daniel Chartrand ◽  
Nina Heidary ◽  
Laura C. Pardo-Perez ◽  
Khoa Ly ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Ag Nanoparticles ◽  
Surface Reaction ◽  
Co2 Reduction ◽  
Catalytic Efficiency ◽  
Reduction Reaction ◽  
Zeolitic Imidazolate Framework ◽  
Catalytic Systems ◽  
Raman Spectroscopic ◽  
Key Aspects

<div>Electrocatalytic reduction of carbon dioxide (CO2R) to fuels and chemicals is a pressing scientific</div><div>and engineering challenge that is, in part, hampered by a lack of understanding of the surface reaction</div><div>mechanism, even for relatively simple systems. While many efforts have been dedicated to promoting CO2R</div><div>on catalytic surfaces by tuning composition, morphology, and defects, the role of the reaction environment</div><div>around the active site, and how this can be leveraged to modulate CO2R, is less clear. To this end, we</div><div>focused on a model CO2R catalyst, Ag nanoparticles, and carried out a combined electrocatalytic and</div><div>operando Raman spectroscopic investigation of CO2R on their surfaces. Bare Ag and chemically modified</div><div>Ag nanoparticles were investigated to understand how the surface reaction environment dictates</div><div>intermediate binding and catalytic efficiency en route to CO generation. The results revealed that the</div><div>primary product on Ag is CO, which is formed through a doubly-bound CObridge configuration. In contrast,</div><div>electrografted imidazole and polyvinylpyrrolidone (PVP)-coated Ag feature CO in a singly-bound COatop</div><div>configuration on their surfaces, whereas porous zeolitic-imidazolate framework-coated Ag was observed</div><div>to bind both CObridge and COatop. Further, another function of the Ag surface modifications is to dictate the</div><div>type of Ag surface sites which form Ag-C bonds with CO2R intermediates. Through analysis of the of</div><div>electrochemical and spectroscopic data, we deduce which key aspects of CO2R on Ag surface render a</div><div>CO2R system efficient and show how surface chemistry dictates diverging CO2R surface reaction</div><div>mechanisms. The insights gained here are important as they provide the community with a greater</div><div>understanding of heterogeneous CO2R and can be further translated to a number of catalytic systems. </div>

Development of a Polarized Raman Spectroscopic Probe for Caries Assessment

2010 ◽  
Author(s):  
Lin-P’ing Choo-Smith ◽  
Eric Marple ◽  
Mark Hewko ◽  
P. M. Champion ◽  
L. D. Ziegler
Keyword(s):  
Raman Spectroscopic ◽  
Polarized Raman ◽  
Caries Assessment ◽  
Spectroscopic Probe

Evolution of Raman Spectra in Ion Irradiated MoS2 Atomic Layers: Computational and Experimental Studies

2020 ◽  
Vol 20 (12) ◽  
pp. 7522-7529
Author(s):  
Tanmay Mahanta ◽  
Jyoti Shakya ◽  
Tanuja Mohanty
Keyword(s):  
Raman Spectra ◽  
Phonon Dispersion ◽  
Ion Irradiation ◽  
Computational Study ◽  
Experimental Studies ◽  
Heavy Ion ◽  
Peak Position ◽  
Acoustic Mode ◽  
Raman Spectroscopic ◽  
External Strain

Herein we report the existence of biaxial strain in swift heavy ion irradiated Molybdenum disulfide (Mos2) as confirmed from Raman spectroscopic measurement and computational study. Defect induced external strain modifies the electronic structure and phonon frequency of the material. In this work, chemically exfoliated Mos2 nanosheets have been exposed to 70 MeV Ni+7 ion irradiation from varying fluence. The Raman spectra reveal that the defect induced LA(M) peak (longitudinal acoustic mode of Phonon at M point) evolves linearly with ion fluence, besides that several other new peaks appear and become visible in Raman spectra thus relaxing Raman fundamental selection rule. Theoretically, simulated Phonon dispersion also supports the fact that tensile strain results in the red shifting of the Raman peak position. The increment of the defect induced LA(M) peak intensity with increasing ion fluence could be a measure of defect quantitatively. This study will be beneficial in the application of external strain to engineer properties of Mos2 as well as understanding the degree of strain inside it quantitatively.

scholarly journals Raman Spectroscopic Study of As-Deposited and Exfoliated Defected Graphene Grown on (001) Si Substrates by CVD

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
T. I. Milenov ◽  
E. Valcheva ◽  
V. N. Popov
Keyword(s):  
Spectroscopic Study ◽  
Chemical Vapor ◽  
Spectroscopic Studies ◽  
Si Substrate ◽  
Raman Spectroscopic ◽  
Si Substrates ◽  
Raman Spectroscopic Study ◽  
Graphene Films ◽  
Polarized Raman ◽  
Defected Graphene

We present here results on a Raman spectroscopic study of the deposited defected graphene on Si substrates by chemical vapor deposition (thermal decomposition of acetone). The graphene films are not deposited on the (001) Si substrate directly but on two types of interlayers of mixed phases unintentionally deposited on the substrates: а diamond-like carbon (designated here as DLC) and amorphous carbon (designated here as αC) are dominated ones. The performed thorough Raman spectroscopic study of as-deposited as well as exfoliated specimens by two different techniques using different excitation wavelengths (488, 514, and 613 nm) as well as polarized Raman spectroscopy establishes that the composition of the designated DLC layers varies with depth: the initial layers on the Si substrate consist of DLC, nanodiamond species, and C70 fullerenes while the upper ones are dominated by DLC with an occasional presence of C70 fullerenes. The αC interlayer is dominated by turbostratic graphite and contains a larger quantity of C70 than the DLC-designated interlayers. The results of polarized and unpolarized Raman spectroscopic studies of as-grown and exfoliated graphene films tend to assume that single- to three-layered defected graphene is deposited on the interlayers. It can be concluded that the observed slight upshift of the 2D band as well as the broadening of 2D band should be related to the strain and doping.

A Polarized Raman Spectroscopic Method for Advanced Analyses of the Osteon Lamellar Structure of Human Bone

2021 ◽  
Author(s):  
Giuseppe Pezzotti ◽  
Eiji Ishimura ◽  
Ryosuke Inai ◽  
Wenliang Zhu ◽  
Taigi Honma ◽  
...  
Keyword(s):  
Lamellar Structure ◽  
Spectroscopic Method ◽  
Human Bone ◽  
Raman Spectroscopic ◽  
Polarized Raman
Sign in / Sign up

Export Citation Format

Share Document