求助Gaussian计算XPS能谱步骤 - 计算化学公社

The core level binding energies of both C 1s and N 1s were ob-tained from the orbital energies using the modified Koopmans theory package within Gaussian 09. The Becke three-parameter Lee-Yang-Parr (B3LYP) hybrid functional and a 6-31 1G(p,d) basis set [56] was used to perform the geometry optimization. To calculate the C 1s XPS spectra, a linear correction factor was used (BEcorrected¼ BEB3LYP(eV)*0.9698 t 19.94) [45]. We note that this estimate does not take into account the electron rearrangement,but has been found to provide a reasonable estimate for the binding energies using this simple linear correction factor. Using this linear equation, a deviation of more than 0.40 eV from the average calculated binding energy of a coronene structure (284.6 eV) was considered significant for this study [45]. Model compounds such as acridine, aminoanthracene, carbazole, and melamine have been analyzed to confirm the validity of the computational method presented here. The linear correction factor used for the C 1s spectra is not valid for the N 1s spectra. As such, for the simulation of the N1s XPS spectra, a scaling factor of 1.038, obtained from dividing the experimental value of acridine (398.8 eV) by the calculated value of acridine (384.03 eV), was multiplied to all of calculated binding energies to compensate for the difference be-tween the calculated values and experimental values [57,58].Several defects, including nitrogenated functional groups, were created on the coronene structure to evaluate the effects of various carbon bonding structures proposed to be predominant in the chars and the likely shifts associated with both the C 1s and N 1s core level binding energies [54]. We also estimated the binding energy of oxygen when bonded to nitrogen as found in nitrogen oxides, where water was used as the reference structure. Using the infor-mation obtained from the DFT-based calculations, such as the peak position, the deconvolution process of the char was realized in an in-house excel based routine to enable us better to tune the fitting parameters, such as the asymmetry factor (TS), the asymmetric tailing factor (TL), and the G-L ratio.