Theoretical Investigation of Al K-edge X-ray Absorption Spectra of Al, AlN and Al&lt;SUB&gt;2&lt;/SUB&gt;O&lt;SUB&gt;3&lt;/SUB&gt;

Mogi, Masato; Yamamoto, Tomoko; Mizoguchi, Teruyasu; Tatsumi, Kazuyoshi; Yoshioka, Satoru; Kameyama, Satoru; Tanaka, Isao; Adachi, Hirohiko

doi:10.2320/matertrans.45.2031

Cited by 26 publications

(22 citation statements)

References 26 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Mogi et al (2004) and Tatsumi et al (2005) reported similar calculations, and found that the experimental chemical shifts are reproduced using an allelectron method. The calculated spectra in the present method are compared with experiments in Fig.…”

Section: Elnes Calculation With the Pseudopotential Methodssupporting

confidence: 64%

Density Functional Theory for ELNES in STEM-EELS

Mizoguchi¹

2014

Scanning Transmission Electron Microscopy of Nanomaterials

View full text Add to dashboard Cite

In this chapter, density functional theory (DFT) is described for calculation of electron energy-loss near-edge structure (ELNES) obtained in STEM-EELS. Fine structure in ELNES originates from an electron transition from a coreorbital to unoccupied bands. The spectral profile of ELNES reflects the partial density of states (PDOS) of the unoccupied bands, and can provide information about electronic structures and chemical bonding around objective atoms in materials. OverviewRecent improvements in monochromators and aberration correctors give tremendous benefits for measurements of ELNES in STEM. With the aid of a monochromator, better than 0.1 eV energy resolution can be achieved, and this improvement enables us to obtain finer spectral profiles, namely more detailed electronic structure information (Terauchi et al., 1999;Tiemeijer, 1999). The spatial resolution of ELNES now reaches to sub-Å with the aid of an aberration corrector for the incident electron probe. As described in Chapter 7, ELNES observations from a single atomic column are now possible using modern STEM systems equipped with aberration correctors (Kimoto et al., 2007;Muller et al., 2008;Varela et al., 2004). In addition to the energy and spatial resolutions, time-resolved ELNES has also been developed recently Scanning Transmission Electron Microscopy of Nanomaterials Downloaded from www.worldscientific.com by UNIVERSITY OF CALIFORNIA @ SAN DIEGO on 04/12/15. For personal use only.

show abstract

Section: Elnes Calculation With the Pseudopotential Methodssupporting

confidence: 64%

Density Functional Theory for ELNES in STEM-EELS

Mizoguchi¹

2014

Scanning Transmission Electron Microscopy of Nanomaterials

View full text Add to dashboard Cite

show abstract

“…38 XANES calculations were performed at the Al K-edge for the aqueous octahedral Al 3+ , α-Al 2 O 3 , aqueous tetrahedral Al-(OH) 4 − , and tetrahedral sodium aluminate (NaAlO 2 ) systems, respectively. Previous studies of the Al K-edge XANES have used a plane-wave pseudopotential method 39,40 for Al, AlN, and α-Al 2 O 3 , and studies of aqueous Al(H 2 O) 6 3+ clusters using both "transition state" DFT 41 and a discrete variational (DV) molecular orbital methods. 42,43 In all the ΔSCF and XANES calculations the Sapporo-QZP-2012 all electron basis set 44 was used for the single absorbing Al site, whereas the surrounding O and H atoms were treated with the 6-311G** basis set 45 and the Stuttgart RLC ECPs 46 were used to treat the surrounding Al atoms in the solid-state α-Al 2 O 3 , and tetrahedral sodium aluminate systems, respectively.…”

mentioning

confidence: 99%

Electronic and Chemical State of Aluminum from the Single- (K) and Double-Electron Excitation (KL_II&III, KL_I) X-ray Absorption Near-Edge Spectra of α-Alumina, Sodium Aluminate, Aqueous Al³⁺·(H₂O)₆, and Aqueous Al(OH)₄^–

Fulton¹,

Govind²,

Huthwelker

et al. 2015

J. Phys. Chem. B

View full text Add to dashboard Cite

We probe, at high energy resolution, the double electron excitation (KLII&II) X-ray absorption region that lies approximately 115 eV above the main Al K-edge (1566 eV) of α-alumina and sodium aluminate. The two solid standards, α-alumina (octahedral) and sodium aluminate (tetrahedral), are compared to aqueous species that have the same Al coordination symmetries, Al(3+)·6H2O (octahedral) and Al(OH)4(-) (tetrahedral). For the octahedral species, the edge height of the KLII&III-edge is approximately 10% of the main K-edge; however, the edge height is much weaker (3% of K-edge height) for Al species with tetrahedral symmetry. For the α-alumina and aqueous Al(3+)·6H2O the KLII&III spectra contain white line features and extended absorption fine structure (EXAFS) that mimics the K-edge spectra. The KLII&III-edge feature interferes with an important region in the EXAFS spectra of the crystalline and aqueous standards. The K-edge spectra and K-edge energy positions are predicted using time-dependent density functional theory (TDDFT). The TDDFT calculations for the K-edge X-ray absorption near-edge spectra (XANES) reproduce the observed transitions in the experimental spectra of the four Al species. The KLII&II and KLI onsets and their corresponding chemical shifts for the four standards are estimated using the delta self-consistent field (ΔSCF) method.

show abstract

“…6c,d, respectively, exhibit temperature-dependent changes. It is noted that Al doped in amber glasses are mostly in the metallic state as featured by a peak at 1560 eV 29,31 , and that the metallic Al peak intensity decreases as temperature increases. Interestingly, the Al 0 peak (represented by the dashed line in Fig.…”

Section: Resultsmentioning

confidence: 99%

On the unusual amber coloration of nanoporous sol-gel processed Al-doped silica glass: An experimental study

Chang

Arango

et al. 2019

Sci Rep

View full text Add to dashboard Cite

Silica is the most abundant component on the earth’s surface. It plays an important role in many natural processes. Silica is also a critical material for a wide range of technical applications such as in optics and electronics. In this work, we discuss our recent experimental observation of the unusual amber coloration of aluminum doped sol-gel glass that has not been reported in the past. We characterized Al-doped sol-gel glasses, prepared at different sintering temperature, using a plethora of techniques to investigate the origin of this unusual coloration and to understand their structural and chemical properties. We used these experimental results to test a number of possible coloring mechanisms. The results suggested this coloring is likely caused by temperature-dependent aluminum-associated defect centers associated with different amorphous-to-crystalline ratios of the annealed sol-gel silica glass structures.

show abstract

Theoretical Investigation of Al K-edge X-ray Absorption Spectra of Al, AlN and Al<SUB>2</SUB>O<SUB>3</SUB>

Cited by 26 publications

References 26 publications

Density Functional Theory for ELNES in STEM-EELS

Density Functional Theory for ELNES in STEM-EELS

Electronic and Chemical State of Aluminum from the Single- (K) and Double-Electron Excitation (KL_II&III, KL_I) X-ray Absorption Near-Edge Spectra of α-Alumina, Sodium Aluminate, Aqueous Al³⁺·(H₂O)₆, and Aqueous Al(OH)₄^–

On the unusual amber coloration of nanoporous sol-gel processed Al-doped silica glass: An experimental study

Contact Info

Product

Resources

About

Theoretical Investigation of Al K-edge X-ray Absorption Spectra of Al, AlN and Al<SUB>2</SUB>O<SUB>3</SUB>

Cited by 26 publications

References 26 publications

Density Functional Theory for ELNES in STEM-EELS

Density Functional Theory for ELNES in STEM-EELS

Electronic and Chemical State of Aluminum from the Single- (K) and Double-Electron Excitation (KLII&III, KLI) X-ray Absorption Near-Edge Spectra of α-Alumina, Sodium Aluminate, Aqueous Al3+·(H2O)6, and Aqueous Al(OH)4–

On the unusual amber coloration of nanoporous sol-gel processed Al-doped silica glass: An experimental study

Contact Info

Product

Resources

About

Electronic and Chemical State of Aluminum from the Single- (K) and Double-Electron Excitation (KL_II&III, KL_I) X-ray Absorption Near-Edge Spectra of α-Alumina, Sodium Aluminate, Aqueous Al³⁺·(H₂O)₆, and Aqueous Al(OH)₄^–