Modulation of the electronic structure of polyconjugated organic molecules by geometry relaxation: A discussion based on local Raman parameters

Castiglioni, Chiara; Milani, Alberto; Fazzi, Daniele; Negri, Fabrizia

doi:10.1016/j.molstruc.2010.12.021

Cited by 6 publications

(7 citation statements)

References 64 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Using this excitation line, the resonance effect occurs with the electronic absorption of the chromophoric group responsible for the π→π* electronic transition of its molecular structure [32,37,55,61]. According to the literature, the electronic absorption of chlorophyll-a occurs out of the green region, more specifically at 450 and 675 nm, with bands relatively strong and which high molar absorptivity coefficients (ε).…”

Section: Resultsmentioning

confidence: 99%

“…Carotenoids are a very special family consisting over 400 conjugated polyenes with C40 substituted and unsubstituted/unsaturated carbon-carbon chains and, jointly with chlorophyll compounds, are responsible for radiation absorptions, mainly in the visible region of the electromagnetic spectrum [33,[50][51][52][53]. The Raman spectra profile of these type of polyunsaturated chain present three characteristic bands located at specific wavenumbers, in the region between 1600-1000 cm -1 which are definitive data for those pigments characterization by Raman spectroscopy [38,39,43,54,55]. These bands are specifically located at ~ 1500 (v 1 ), 1160 (v 2 ) and 1000 cm -1 (ρ 3 ), assigned respectively to (C=C) and (C-C) stretching and (C-CH 3 ) deformation modes.…”

Section: Cylindrospermopsis Raciborskii (Cyrf) and Microcystis Aerugimentioning

confidence: 95%

See 1 more Smart Citation

Study of carotenoids in cyanobacteria by Raman spectroscopy

Oliveira

Miranda

Soares

et al. 2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

View full text Add to dashboard Cite

Section: Resultsmentioning

confidence: 99%

Section: Cylindrospermopsis Raciborskii (Cyrf) and Microcystis Aerugimentioning

confidence: 95%

Study of carotenoids in cyanobacteria by Raman spectroscopy

Oliveira

Miranda

Soares

et al. 2015

Spectrochimica Acta Part A: Molecular and Biomolecular Spectros

View full text Add to dashboard Cite

“…Many vibrational transitions show non-negligible Raman intensity, thus demonstrating the possibility of detecting cumulenic chains by means of Raman spectroscopy. Interestingly, the interplay between the activation of out-of-Γ normal modes and the molecular parameters governing Raman activity [ 29 , 74 ] generates a detectable Raman signal for LO modes other than ECC in cumulenes, as shown in Fig. 3 (b,c).…”

Section: Reviewmentioning

confidence: 99%

Raman spectroscopy as a tool to investigate the structure and electronic properties of carbon-atom wires

Milani¹,

Tommasini²,

Russo³

et al. 2015

Beilstein J. Nanotechnol.

Self Cite

102

View full text Add to dashboard Cite

SummaryGraphene, nanotubes and other carbon nanostructures have shown potential as candidates for advanced technological applications due to the different coordination of carbon atoms and to the possibility of π-conjugation. In this context, atomic-scale wires comprised of sp-hybridized carbon atoms represent ideal 1D systems to potentially downscale devices to the atomic level. Carbon-atom wires (CAWs) can be arranged in two possible structures: a sequence of double bonds (cumulenes), resulting in a 1D metal, or an alternating sequence of single–triple bonds (polyynes), expected to show semiconducting properties. The electronic and optical properties of CAWs can be finely tuned by controlling the wire length (i.e., the number of carbon atoms) and the type of termination (e.g., atom, molecular group or nanostructure). Although linear, sp-hybridized carbon systems are still considered elusive and unstable materials, a number of nanostructures consisting of sp-carbon wires have been produced and characterized to date. In this short review, we present the main CAW synthesis techniques and stabilization strategies and we discuss the current status of the understanding of their structural, electronic and vibrational properties with particular attention to how these properties are related to one another. We focus on the use of vibrational spectroscopy to provide information on the structural and electronic properties of the system (e.g., determination of wire length). Moreover, by employing Raman spectroscopy and surface enhanced Raman scattering in combination with the support of first principles calculations, we show that a detailed understanding of the charge transfer between CAWs and metal nanoparticles may open the possibility to tune the electronic structure from alternating to equalized bonds.

show abstract

“…A deeper analysis of the D band reveals that it is associated with ring breathing C–C stretching motions, according to the assignation of the PAH vibrations of large extent aromatic hydrocarbons. , Therefore, the presence of different D bands in SHA, at 1305, 1285 (shoulder), 1250, and 1230 cm –1 , is attributable to the existence of PAHs bearing a different aromatic extent and different substituents. The latter bands were hardly observed in other HA, probably because of the higher amount of PAH structures in the SHA studied here.…”

Section: Results and Discussionmentioning

confidence: 99%

Stimulated Adsorption of Humic Acids on Capped Plasmonic Ag Nanoparticles Investigated by Surface-Enhanced Optical Techniques

et al. 2019

View full text Add to dashboard Cite

The adsorption of humic substances on Ag nanoparticles (AgNPs) is of crucial environmental importance and determines the toxicity of these NPs and the structure of adsorbed organic matter. In this work, the adsorption of two standard soil and leonardite International Humic Substances Society humic acids was studied on AgNPs of different sizes, shapes (spherical and star-like), and interfacial chemical compositions. Surface-enhanced optical (Raman and fluorescence) spectroscopies were used to follow the specific chemical groups involved in this adsorption. By means of the latter optical techniques, information regarding the binding mechanism and the macromolecular aggregation can be deduced. The influence of the surface chemical composition induced by the different functionalizations of the interfaces of these NPs is highly important regarding the chemical interactions of these complex organic macromolecules. The surface functionalization with positively charged alkyl diamines led to a large increase in the adsorption as well as a strong structural rearrangement of the macromolecule once adsorbed onto the surface.

show abstract

Modulation of the electronic structure of polyconjugated organic molecules by geometry relaxation: A discussion based on local Raman parameters

Cited by 6 publications

References 64 publications

Study of carotenoids in cyanobacteria by Raman spectroscopy

Study of carotenoids in cyanobacteria by Raman spectroscopy

Raman spectroscopy as a tool to investigate the structure and electronic properties of carbon-atom wires

Stimulated Adsorption of Humic Acids on Capped Plasmonic Ag Nanoparticles Investigated by Surface-Enhanced Optical Techniques

Contact Info

Product

Resources

About