Kazunaka Endo

Kinetic energies to analyze the experimental auger electron spectra by density functional theory calculations

In the Auger electron spectra (AES) simulations, we define theoretical modified kinetic energies of AES in the density functional theory (DFT) calculations. The modified kinetic energies correspond to two final-state holes at the ground state and at the transition-state in DFT calculations, respectively. This method is applied to simulate Auger electron spectra (AES) of 2nd periodic atom (Li, Be, B, C, N, O, F)-involving substances (LiF, beryllium, boron, graphite, GaN, SiO2, PTFE) by deMon DFT calculations using the model molecules of the unit cell. Experimental KVV (valence band electrons can fill K-shell core holes or be emitted during KVV-type transitions) AES of the (Li, O) atoms in the substances agree considerably well with simulation of AES obtained with the maximum kinetic energies of the atoms, while, for AES of LiF, and PTFE substance, the experimental F KVV AES is almost in accordance with the spectra from the transitionstate kinetic energy calculations.

IR and Py-GC/MS spectral simulation of polymer film by quantum chemical and quantum molecular dynamics calculations using the polymer models

We have simulated IR and pyrolysis gas chromatography mass spectrometry (Py-GCMS) spectra of six polymers (PE, PP, PS, PET, N6, PVDF) with the density-functional theory and quantum molecular dynamics calculations on model oligomers. In the former calculations, experimental harmonic frequencies of the polymers have been assigned from the simulated IR spectra. In the latter QMD calculations on thermal decomposition of polymer models, the approximated mass spectra of six (PE, PP, PS, PET, N6, PVDF) polymers were almost in good accordance with the experimental results in Py-GC/MS, although we adjusted the decomposition temperatures to 2240, 2520, and 2800 K as the average absolute deviation of 8%.

DFT Simulation of Electron Spectra for Auger Electron and Photoelectron Spectra of Lithium Compounds

Abstract(Li, O, F)-Auger electron, and X-ray photoelectron spectra (AES, VXPS) of solid lithium compounds (Li metal, LiCl, LiF, Li2O) are simulated by deMon density functional theory (DFT) calculations using the model molecules of the unit cell. Calculated valence XPS, core-electron binding energies (CEBE)s, and Li-, O-, and F-KVV AES for the substances correspond considerably well to experimental results. For the calculation of VXPS, the observed spectra of Li2O pellet with chemisorbed CO2 almost show agreement with simulation curve of the valence XPS according to the model for the 1/1 ratio of Li2O/Li2CO3. In the case of AES calculation, we analyze the experimental AES with our modified Auger electron kinetic energy calculation method which corresponds to the two final-state holes at the ground state and at the transition-state in DFT calculation by removing 1 and 2 electrons, respectively. Experimental KVV AES of the Li atom, and (O, F) KVV AES of (Li2O and LiF) in the substances almost agree well to the AES calculated with maximum kinetic energies at the ground state, and at the transition-state, respectively.

Valence XPS, IR, and Solution 13C NMR Spectral Analysis of Representative Polymers by Quantum Chemical Calculations

Valence XPS, IR, and solution 13C NMR spectra of representative polymers (PE, PS, PMMA, PVC) have been analyzed using the model oligomers from B3LYP/6-31+G(d, p) basis calculations in GAUSSIAN 09. We simulated valence XPS of the polymers by the negative of orbital energies of the ground electronic state at the geometry optimization of the model oligomers. Simulated IR spectra, and solution 13C NMR chemical shifts of polymers were obtained from the other SCF calculations of B3LYP/6-31+G(d, p) basis using atomic coordinates of the model molecules at the geometry optimization, in order to gain the vibrational frequencies and nuclear magnetic shielding tensors, respectively. We have clarified the electronic states of some polymers from the good accordance of simulated VXPS, IR spectra, and solution 13C NMR shifts of polymer models molecules with the experimental ones of the polymers.

Depth Profile Assignments of nm and μm Orders by Quantum Chemical Calculations for Chitosan Films Modified by Kr + Beam Bombardment

Valence X-ray photoelectron and Raman spectra of a chitosan film modified by Kr+ion beam bombardment were analyzed from quantum chemical calculations. Experimental Raman spectra of the carbonized film with Kr+ion bombardment were found to be due to four component contributions of chitosan (Chito), diamond-like carbon (DLC), graphite (GP), and amorphous carbon (AC). By considering the four components contribution, we performed depth profile assignments in nm and μm ranges of the chitosan film in valence X-ray photoelectron spectroscopy and Raman shift experiments from calculations of the statistical average of orbital potential (SAOP) method of Amsterdam density functional (ADF) program, and B3LYP/6-31G(d, p) level in GAUSSIAN 09 software, respectively, using the model molecules. Carbonizations of the film by Kr+irradiation were obtained as Chito: DLC: AC: GP = 2:1:0.5:0.375 in the μm range from Raman shift analysis, while they were determined as Chito: DLC: AC: GP = 2:1:1:2 in the nm range from valence X-ray photoelectron spectral analysis.