Theoretical X-ray absorption spectroscopy database analysis for oxidised 2D carbon nanomaterials

Abstract

A theoretical database approach for the composition and decomposition of near-edge X-ray absorption fine structure spectra is presented.

Influence of surface chemistry on optical, chemical and electronic properties of blue luminescent carbon dots

“…Four main features at 285.2 (A), 287.5 (B), 288.9 (C) and 294-297 (D) eV are observed. In addition, DFT calculations using an individual-atom decomposition method were performed, 28 to enable the assignment of the different features of the C K-edge XA spectra (see Table S1, ESI †). According to the calculation and previous experimental studies on carbon nanomaterials, feature A at 285.2 eV can be assigned univocally to the excitation of core electrons into π* CvC orbitals.…”

“…Theoretical calculations on carbon K-edge XAS were performed in 28 different model molecules of both coronene and circumcoronene sizes for a total of 1049 carbon atoms as discussed in more detail in ref. 28. The molecular structure was first optimized using density functional theory (DFT) with the Ahlrichs def2-SVP basis set and the TPSS meta-GGA functional.…”

X-ray Raman scattering for bulk chemical and structural insight into green carbon

“…Molecular structures were initially constructed in Avogadro 1.1.1. 32 Ground state geometry optimisation calculations for these structures were carried out using the ORCA 4.0 code with a B3LYP functional, def2-SVP basis set 33 and third order dispersion correction with Becke-Jones damping (D3BJ). 34,35 To reduce computational expense, the RIJCOSX approximation was used with appropriate def2-SVP/J basis sets.…”

Uncovering the Charge Transfer between Carbon Dots and Water by In Situ Soft X-ray Absorption Spectroscopy

“…This observation is in agreement with their more efficient electron transfer to molecular catalysts in aqueous homogenous dispersion previously reported for photocatalytic H2 evolution. 7,27 The features in the range between 286 and 288 eV can be assigned to the π*C-C-O transitions in oxygen-containing groups, 9,28 whose intensities showed significant changes in the in situ TIY-XA spectra compared with the TEY-XA spectra obtained in the solid state. The shoulder at 535.5 eV for the O 1s → π*C-OH of the carboxyl groups 9 observed for CDs samples in the TEY-XA spectra at O K-edge ( Figure S2) suggesting that the C-O features mainly originates from carboxyl groups.…”