Time dependent density functional theory study of the near-edge x-ray absorption fine structure of benzene in gas phase and on metal surfaces

Abstract

Time dependent density functional theory study of the near-edge x-ray absorption fine structure of benzene in gas phase and on metal surfaces Near edge X-ray absorption fine structure measurements (XANES) and extended x-ray absorption fine structure measurements (EXAFS) of the valence state and coordination of antimony in doped nanocrystalline SnO 2 A new spectroelectrochemical cell to investigate the structure of Pt/Au nanoclusters using Pt and Au K-edge X-ray absorption fine structure (XAFS) measurements under the electrochemical conditions is developed. K-edge XAFS measurements for Pt and Au require a sample as thick as 1-2 cm, which prevents homogeneous potential distribution. We can measure in situ Pt and Au K-edge XAFS spectra and determine reasonable electrochemical surface areas using our developed spectroelectrochemical cell. This work provides a new approach to analyze Pt/Au core-shell nanoclusters. The new cell is designed to be applied to both spectra with high absorption-edge energies such as the K-edge of Pt and Au and those with low absorption-edge energy such as Pt Ledge. © 2014 AIP Publishing LLC.

Time-dependent density functional theory calculations of near-edge X-ray absorption fine structure with short-range corrected functionals

“…13,15,43 This makes the calculation of core excited states of comparable expense to computing valence excited states whilst introducing a negligible error. 44 For small systems, the error can be evaluated directly by comparing the results from the calculations with the truncation of the excitation space to those from calculations with the full excitation space. For a range of core excitations from 1s orbitals, the largest error observed was 0.01 eV in the excitation energy and 0.011 in the oscillator strength.…”

“…For a range of core excitations from 1s orbitals, the largest error observed was 0.01 eV in the excitation energy and 0.011 in the oscillator strength. 44 In standard long-range corrected functionals, the exchangecorrelation functional can be expressed as…”

High-Resolution Near-Edge X-ray Absorption Fine Structure Study of Condensed Polyacenes

“…22 Other constrained optimization procedures were applied to obtain the core-ionized species used as a reference for the CI to describe these excited states. 10,23,24 Approaches based in the Density Functional Theory (DFT) were also explored, like those based on TDDFT 25,26 or even applying more detailed procedures, like taking Slater's transition states 27,28 or applying the ∆DFT using double-basis 17 to recover the electronic relaxation effects. Our choice of the electronic structure method in the present work was given by its versatility to calculate the hundreds of single-geometry points needed to the Nuclear Ensemble method without losing relevant aspects related to the description of the electronic correlation of the excited states in these molecules 29 .…”

Density functional theory study of the near edge X-ray absorption fine structure and infrared spectroscopy of acetylene and benzene on group IV semiconductor surfaces

“…For core excitations, this approximation introduces a very small error in the computed excitation energies [44]. We have used this approach to study the NEXAFS [30,44] and electronic [45,46] spectroscopy of a variety of molecules adsorbed on surfaces. For the systems studied here, electronic excitations from the two carbon 1s orbitals of acetylene and the six carbon 1s orbitals of benzene to the entire virtual space are included in the excitation space.…”