A comparative theoretical study on core-hole excitation spectra of azafullerene and its derivatives

Abstract

The core-hole excitation spectra-near-edge x-ray absorption spectroscopy (NEXAFS), x-ray emission spectroscopy (XES), and x-ray photoelectron spectroscopy (XPS) shake-up satellites have been simulated at the level of density functional theory for the azafullerene C 59 N and its derivatives (C 59 N) + , C 59 HN, (C 59 N) 2 , and C 59 N-C 60 , in which the XPS shake-up satellites were simulated using our developed equivalent core hole Kohn-Sham (ECH-KS) density functional theory approach [B. Gao, Z. Wu, and Y. Luo, J. Chem. Phys. 128, 234704 (2008)] which aims for the study of XPS shake-up satellites of large-scale molecules. Our calculated spectra are generally in good agreement with available experimental results that validates the use of the ECH-KS method in the present work. The nitrogen K-edge NEXAFS, XES, and XPS shake-up satellites spectra in general can be used as fingerprints to distinguish the azafullerene C 59 N and its different derivatives. Meanwhile, different carbon K-edge spectra could also provide detailed information of (local) electronic structures of different molecules. In particular, a peak (at around 284.5 eV) in the carbon K-edge NEXAFS spectrum of the heterodimer C 59 N-C 60 is confirmed to be related to the electron transfer from the C 59 N part to the C 60 part in this charge-transfer complex. © 2014 AIP Publishing LLC.

Spectromicroscopy of C60 and azafullerene C59N: Identifying surface adsorbed water

“…By contrast good agreement is found between our measured and calculated N 1 s spectra, notably in the features in the extended σ* states and the low energy shoulder to the 401.5 eV peak. We note that our theoretical and experimental data correctly reproduces the key spectral features found in a recent simulated (C 59 N) 2 NEXAFS N 1 s spectrum 31 , including primary peak spacings and the presence of the small pre-peak shoulder. This gives us additional confidence in our results…”

Structural and spectral properties of a non-classical C58 isomer and its fluorinated derivatives in theory

“…In the XES spectrum, the transition moment between valence and core orbital is computed, and the ground state electronic structure is utilized to calculate the adiabatic approximation intensities. 70 Further convolution by a Lorentzian function with FWHM = 0.5 eV has been applied to generate the final XES spectra.…”

Efficient simulation of near-edge x-ray absorption fine structure (NEXAFS) in density-functional theory: Comparison of core-level constraining approaches

“…The FCH approach was successfully applied to the simulation of X-ray absorption spectra of water and ice 13 , and fullerenes 57,76 , while the TP approximation was found to perform well for organic molecules 53,77,78 . Interestingly, the obvious GTP analog to the GTS variant has not been considered before, and we include it in this study for completeness.…”