Browse
Submit Data
Databases
API
Help

Dataset Information

5 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Raman and ROA analyses of twisted anthracenes: connecting vibrational and electronic/photonic structures.

ABSTRACT: In this article the Raman and Raman Optical Activity (ROA) spectra of a series of enantiomeric twisted anthracenes are presented. The evolution of their vibrational spectra is understood in the context of the variation of π-electron delocalization as a result of the twisting imparted by the belt structure and in terms of the modulation of the resonance Raman/ROA effects which are photonic properties also tuned by anthracene twisting. The Raman/ROA vibrational spectra are simulated by several theoretical approaches to account for their vibrational and electronic properties including the theoretical evaluation of resonance effects. We furthermore incorporate a vibrational and ROA activity dissection analysis as provided in the Pyvib2 program valid to establish correlations among vibrational modes of different molecules with different electronic structures and equivalent vibrational dynamics. This paper is one of the very first attempts to use ROA spectroscopy in π-conjugated molecules with twisted and helical morphologies that contrast with the well-known cases of ROA studies of chiral helicenes in which the impact of π-electron delocalization in the electronic/photonic/vibrational (Raman/ROA) spectra is negligible.

SUBMITTER: Palomo L

PROVIDER: S-EPMC8246141 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Study of Electronic and Vibrational Structures of Reduced, Neutral, and Oxidized Ni3(dpa)4X2 Using Density Functional Theory and Raman Spectroscopy.

Project description:The electronic and vibrational structures of trinickel metal string complexes [Ni3(dpa)4X2]1-,0,1+ (X = Cl, NCS) were investigated using both theoretical calculations and spectroscopic methods. We used the density functional theory (DFT) method B3LYP*-D3, including less exact exchange energy and the van der Waals interaction of metal ions, to obtain the geometries and vibrational structures, which were found to be in excellent agreement with the experimental data. The ground state of Ni3(dpa)4X2 is an antiferromagnetic (AF) singlet state, and the next state is a quintet state, which was detected using temperature-dependent Raman spectroscopy under a magnetic field. The vibrational structure of the quintet state is nearly identical to that of the AF state, according to the measured Raman spectra, except that the stretching of Ni-Cl is blue-shifted from 282.5 cm-1 in the AF state to 283.8 cm-1 in the quintet state. Two oxidized Ni3 complexes were found to have [Ni3]7+ cores, the doublet [Ni3(dpa)4]3+ without axial ligands and the quartet [Ni3(dpa)4X2]+. Complex [Ni3(dpa)4X2]-, which was produced from a reduction reaction by gold nanoparticles at room temperature, consists of a quartet state as the ground state and a doublet state lying nearby.

| S-EPMC7331223 | biostudies-literature

Electronic Structures of Twisted Bilayer InSe/InSe and Heterobilayer Graphene/InSe.

Project description:Building vertical van der Waals heterojunctions between two-dimensional layered materials has become a promising strategy for modulating the properties of two-dimensional materials. Herein, we investigate the electronic structures of non-twisted/twisted bilayer InSe/InSe and heterobilayer graphene/InSe (Gr/InSe) by employing density functional theory calculations. For twisted bilayer InSe/InSes, their interlayer distances and band gaps are almost identical but a bit larger than those of the AB-stacking one due to the spontaneous polarization. Differently, the band gaps of twisted Gr/InSe are found to vary with the rotation angles. Our results provide an effective way to tune the electronic properties of two-dimensional materials.

| S-EPMC8158824 | biostudies-literature

Tunable guided resonance in twisted bilayer photonic crystal.

Project description:We experimentally demonstrate tunable guided resonance in twisted bilayer photonic crystals. Both the numerically and the experimentally obtained transmission spectra feature resonances with frequencies strongly dependent on the twist angle, as well as resonances with frequencies that are largely independent of the twist angle. These resonant features can be well understood with a simple analytic theory based on band folding. Our work illustrates the rich tunable resonance physics in twisted bilayer systems.

| S-EPMC9710865 | biostudies-literature

Modeling the optical properties of twisted bilayer photonic crystals.

Project description:We demonstrate a photonic analog of twisted bilayer graphene that has ultra-flat photonic bands and exhibits extreme slow-light behavior. Our twisted bilayer photonic device, which has an operating wavelength in the C-band of the telecom window, uses two crystalline silicon photonic crystal slabs separated by a methyl methacrylate tunneling layer. We numerically determine the magic angle using a finite-element method and the corresponding photonic band structure, which exhibits a flat band over the entire Brillouin zone. This flat band causes the group velocity to approach zero and introduces light localization, which enhances the electromagnetic field at the expense of bandwidth. Using our original plane-wave continuum model, we find that the photonic system has a larger band asymmetry. The band structure can easily be engineered by adjusting the device geometry, giving significant freedom in the design of devices. Our work provides a fundamental understanding of the photonic properties of twisted bilayer photonic crystals and opens the door to the nanoscale-based enhancement of nonlinear effects.

| S-EPMC8322106 | biostudies-literature

Electronic and vibrational surface-enhanced Raman scattering: from atomically defined Au(111) and (100) to roughened Au.

Project description:In surface-enhanced Raman spectra, vibrational peaks are superimposed on a background continuum, which is known as one major experimental anomaly. This is problematic in assessing vibrational information especially in the low Raman-shift region below 200 cm-1, where the background signals dominate. Herein, we present a rigorous comparison of normal Raman and surface-enhanced Raman spectra for atomically defined surfaces of Au(111) or Au(100) with and without molecular adsorbates. It is clearly shown that the origin of the background continuum is well explained by a local field enhancement of electronic Raman scattering in the conduction band of Au. In the low Raman-shift region, electronic Raman scattering gains additional intensity, probably due to a relaxation in the conservation of momentum rule through momentum transfer from surface roughness. Based on the mechanism for generation of the spectral background, we also present a practical method to extract electronic and vibrational information at the metal/dielectric interface from the measured raw spectra by reducing the thermal factor, the scattering efficiency factor and the Purcell factor over wide ranges in both the Stokes and the anti-Stokes branches. This method enables us not only to analyse concealed vibrational features in the low Raman-shift region but also to estimate more reliable local temperatures from surface-enhanced Raman spectra.

| S-EPMC8162194 | biostudies-literature

Twisted photonic Weyl meta-crystals and aperiodic Fermi arc scattering.

Project description:As a milestone in the exploration of topological physics, Fermi arcs bridging Weyl points have been extensively studied. Weyl points, as are Fermi arcs, are believed to be only stable when preserving translation symmetry. However, no experimental observation of aperiodic Fermi arcs has been reported so far. Here, we continuously twist a bi-block Weyl meta-crystal and experimentally observe the twisted Fermi arc reconstruction. Although both the Weyl meta-crystals individually preserve translational symmetry, continuous twisting operation leads to the aperiodic hybridization and scattering of Fermi arcs on the interface, which is found to be determined by the singular total reflection around Weyl points. Our work unveils the aperiodic scattering of Fermi arcs and opens the door to continuously manipulating Fermi arcs.

| S-EPMC10948390 | biostudies-literature

Diamane-like Films Based on Twisted G/BN Bilayers: DFT Modelling of Atomic Structures and Electronic Properties.

Project description:Diamanes are unique 2D carbon materials that can be obtained by the adsorption of light atoms or molecular groups onto the surfaces of bilayer graphene. Modification of the parent bilayers, such as through twisting of the layers and the substitution of one of the layers with BN, leads to drastic changes in the structure and properties of diamane-like materials. Here, we present the results of the DFT modelling of new stable diamane-like films based on twisted Moiré G/BN bilayers. The set of angles at which this structure becomes commensurate was found. We used two commensurate structures with twisted angles of θ = 10.9° and θ = 25.3° with the smallest period as the base for the formation of the diamane-like material. Previous theoretical investigations did not take into account the incommensurability of graphene and boron nitride monolayers when considering diamane-like films. The double-sided hydrogenation or fluorination of Moiré G/BN bilayers and the following interlayer covalent bonding led to the opening of a gap up to 3.1 eV, which was lower than the corresponding values of h-BN and c-BN. The considered G/BN diamane-like films offer great potential in the future for a variety of engineering applications.

| S-EPMC10004773 | biostudies-literature

Helicity Enhanced Torsion Sensor Based on Liquid Filled Twisted Photonic Crystal Fibers.

Project description:A highly sensitive torsion sensor can be constructed by combining a twisted photonic crystal fiber with a liquid-filled waveguide in its air-hole cladding. The torsion sensitivity of this type of sensor is determined directly by the phase-matching conditions between the fiber core mode and the liquid waveguide mode, which can be improved by tuning the helicity (denoted by the initial twist rate, ?0) of the twisted photonic crystal fiber. The enhancement mechanism of ?0 on the sensitivity of the proposed torsion sensor is investigated theoretically, followed by experimental verifications, and a torsion sensitivity as high as 446 nm?mm?rad-1 can be obtained by tailoring these parameters. Experimental results show that the torsion sensitivity increases with ?0 decreasing from 3.142 to 3.925 rad/mm, which are in consistence with that of the numerical predictions. The demonstrated torsion sensor is expected to contribute to the development of highly sensitive torsion-related photonic crystal fiber devices.

| S-EPMC7085693 | biostudies-literature

Raman

Project description:Raman spectroscopy for pathogen detection and antibiotic resistance identification

| PRJEB59025 | ENA

Raman

Project description:Multi-excitation Raman Spectroscopy Complements Whole Genome Sequencing for Rapid Detection of Bacterial Infection and Resistance in WHO Priority Pathogens

| PRJEB59061 | ENA

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data