001[]
| Fragment | S. | Z. | Quelle | S. | Z. | Typus | Status | (Ersteller) Sichter |
|---|---|---|---|---|---|---|---|---|
| Efa/Fragment 019 02 | 19 | 2-9 | de Groot 2005 | 32 | second paragraph | KomplettPlagiat | Unfertig | (Klgn) |
| Efa/Fragment 028 01 | 28 | 1-16, 19 ff. | Foresman Frisch 1996 | 13, 39, 40 | - | Verschleierung | Unfertig | (Klgn) |
| Efa/Fragment 034 02 | 34 | 2-4, 7 ff. | de Groot 2005 | 33, 34 | - | BauernOpfer | Unfertig | (Klgn) |
| Efa/Fragment 035 01 | 35 | 1-4 | de Groot 2005 | 34 | - | BauernOpfer | Unfertig | (Klgn) |
002[]
| Typus | Gesichtet | ZuSichten | Unfertig | Σ |
|---|---|---|---|---|
| ÜP | 0 | 0 | 0 | 0 |
| KP | 0 | 0 | 1 | 1 |
| VS | 0 | 0 | 1 | 1 |
| BO | 0 | 0 | 2 | 2 |
| KW | 0 | 0 | 0 | 0 |
| KeinP | 0 | 0 | 0 | 0 |
| Σ | 0 | 0 | 4 | 4 |
003[]
| Nr. | Quelle | ÜP | KP | VS | BO | KW | Unfer | Frag | Dubl |
|---|---|---|---|---|---|---|---|---|---|
| 1. | de Groot 2005 | 1 | 2 | 3 | 3 | ||||
| 2. | Chen 1997 | ||||||||
| 3. | Foresman Frisch 1996 | 1 | 1 | 1 |
004[]
| REF (LV) \ Txt-REF | yes | no | ? | Σ |
|---|---|---|---|---|
| yes | 2 | 0 | 0 | 2 |
| no | 0 | 1 | 0 | 1 |
| ? | 0 | 0 | 0 | 0 |
| Σ | 2 | 1 | 0 | 3 |
005[]
4 Fragmente
| [1.] Analyse:Efa/Fragment 019 02 |
| KomplettPlagiat |
|---|
| Untersuchte Arbeit: Seite: 19, Zeilen: 2-9 |
Quelle: de Groot 2005 Seite(n): 32, Zeilen: second paragraph |
|---|---|
| X-ray absorption spectroscopy (XAS) has become an important tool for the characterization of materials as well as for fundamental studies of atoms, molecules, adsorbate, surfaces, liquids and solids [2, 5, 16–18]. The particular assets of XAS spectroscopy are its element specificity and the possibility to obtain detailed information without the presence of any long-range order. Below it will be shown that the x-ray absorption spectrum in some cases is closely related to the empty density of states of a system. As such XAS is able to provide a detailed picture of the local electronic structure of the element studied.
[2] J. H. Guo, Y. Luo, A. Augustsson, S. Kashtanov, J. E. Rubensson, D. Shuh, V. Zhuang, P. Ross, H. Agren, J. Nordgren. Journal of Electron Spectroscopy and Related Phenomena 137-40, 425 (2004) [5] B. M. Messer, C. D. Cappa, J. D. Smith, K. R. Wilson, M. K. Gilles, R. C. Cohen, R. J. Saykally. Journal of Physical Chemistry B 109, 5375 (2005) [16] F. M. F. de Groot. Journal of Electron Spectroscopy and Related Phenomena 67, 529 (1994) [17] S. Eisebitt, J. E. Rubensson, T. Boske, W. Eberhardt. Physical Review B 48, 17388 (1993) [18] J. Stöhr. NEXAFS spectroscopy. Springer-Verlag, Berlin; New York (1992) |
1. Basic aspects of multiplet effects
[...] X-ray absorption spectroscopy (XAS) has become an important tool for the characterization of materials as well as for fundamental studies of atoms, molecules, adsorbates, surfaces, liquids and solids. The particular assets of XAS spectroscopy are its element specificity and the possibility to obtain detailed information without the presence of any long-range order. Below it will be shown that the X-ray absorption spectrum in some cases is closely related to the empty density of states of a system. As such XAS is able to provide a detailed picture of the local electronic structure of the element studied. |
The true source is not given. |
| [2.] Analyse:Efa/Fragment 028 01 |
| Verschleierung |
|---|
| Untersuchte Arbeit: Seite: 28, Zeilen: 1-16, 19 ff. |
Quelle: Foresman Frisch 1996 Seite(n): 13, 39, 40, Zeilen: - |
|---|---|
| [Energy level means the sum of the electronic energy, and the nuclear repulsion and kinetic] energy of the molecule at the specified nuclear configuration. In general this quantity is referred to as the total energy. However, more complete and accurate energy predictions require a thermal or zero-point energy correction, as will be shortly discussed later. The validity of the results of these calculations depends on having reasonable structures for the molecules as input.
Single point energy calculations are performed for many purposes, including the following:
In all cases, it can be performed at any level of theory and with small or large basis sets. [...] Geometry optimization The way the energy of a molecular system varies with small changes in its structure is specified by its potential energy surface. The potential energy surface is a mathematical relationship linking molecular structure and the resultant energy. Geometry optimizations usually attempt to locate minima on the potential energy surface, thereby predicting equilibrium structures of molecular systems. Optimizations can also locate transition structures. A geometry optimization begins at the molecular structure specified as its input, and steps along the potential energy surface. It computes the energy and the gradient at that point, and then determines how far and in which direction to make the next step. The gradient indicates the direction along the surface in which the energy decreases most rapidly from the current point as well as the steepness of that slope. |
[page 13]
[...] A single point energy calculation is a prediction of the energy† and related properties for a molecule with a specified geometric structure. [...] The validity of results of these calculations depends on having reasonable structures for the molecules as input. Single point energy calculations are performed for many purposes, including the following: ✦ To obtain basic information about a molecule. ✦ As a consistency check on a molecular geometry to be used as the starting point for an optimization. ✦ To compute very accurate values for the energy and other properties for a geometry optimized at a lower level of theory. ✦ When it is the only affordable calculation for a system of interest. Single point energy calculations can be performed at any level of theory and with small or large basis sets. † That is, the sum of the electronic energy and nuclear repulsion energy of the molecule at the specified nuclear configuration. This quantity is commonly referred to as the total energy. However, more complete and accurate energy predictions require a thermal or zero-point energy correction (see Chapter 4, p. 68). [page 39] Geometry Optimizations [...] The way the energy of a molecular system varies with small changes in its structure is specified by its potential energy surface. A potential energy surface is a mathematical relationship linking molecular structure and the resultant energy. [page 40] Locating Minima Geometry optimizations usually attempt to locate minima on the potential energy surface, thereby predicting equilibrium structures of molecular systems. Optimizations can also locate transition structures. [...] A geometry optimization begins at the molecular structure specified as its input, and steps along the potential energy surface. It computes the energy and the gradient at that point, and then determines how far and in which direction to make the next step. The gradient indicates the direction along the surface in which the energy decreases most rapidly from the current point as well as the steepness of that slope. |
The true source is not given. |
| [3.] Analyse:Efa/Fragment 034 02 |
| BauernOpfer |
|---|
| Untersuchte Arbeit: Seite: 34, Zeilen: 2-4, 7 ff. |
Quelle: de Groot 2005 Seite(n): 33, 34, Zeilen: - |
|---|---|
| The single particle description of x-ray absorption works well for all K edges and a range of dedicated computer codes exist to calculate the x-ray absorption cross-section. [...] Other dedicated codes have been presented in the review of John Rehr as well as the latest developments in the single electron codes using multiple scattering [56,57]. Cabaret and co-workers describe the new developments in band structure codes and the recently developed PARATEC-based projection method promises to set a new standard for single electron XANES calculations [58]. Applying these one-electron codes (where one-electron applies to a one-electron core excitation, not to the treatment of the valence electrons) to systems such as transition metal oxides or halides one finds excellent agreement for the metal and oxygen K edges, whereas for the other edges, in particular the metal L2,3 edges, the agreement is poor. The reason for this discrepancy is not that the transition matrix is calculated wrongly, but that one does not observe the density of states in such x-ray absorption processes. The reason for the deviation from the transition matrix is the strong overlap of the core wave function with the valence wave functions, as well as valence - valence interaction. This overlap of the wave functions is present also in the ground state, but because all core states are filled, it is not effective and one can approximate the core electrons with their charge. In the final state of an x-ray absorption process a partly filled core state, for example, a 2p5 configuration is existing. In case of investigating a system with a partly filled 3d-band, for example, Ni+2, the final state will have an incompletely filled 3d-band. For Ni+2 this can be approximated as a 3d9 configuration. The 2p-hole and the 3d-hole have radial wave functions that overlap significantly. This wave function overlap is an atomic effect that can be very large. It creates final states that are found after the vector coupling of the 2p and 3d wave functions. This implies that the atomic multiplet effects are of the same order of magnitude in atoms and in solids. In case of s core holes, multiplet effects are effectively reduced to just the exchange interaction between the spin of the s core hole and the spin of the valence electrons. The 1s core states have in all cases a very small exchange interaction, implying that multiplet effects will not be visible significantly. This implies that single electron codes will be effective for all K edges. For multiplet [effects to have a significant effect on the mixing of the L3 and L2 edges, the value of the Slater–Condon parameters must be at least of the same order of magnitude as the spin–orbit coupling separating the two edges.]
[56] J. J. Rehr, R. C. Albers. Reviews of Modern Physics 72, 621 (2000) [57] J. J. Rehr, A. L. Ankudinov. Journal of Electron Spectroscopy and Related Phenomena 114, 1115 (2001) [58] M. Taillefumier, D. Cabaret, A. M. Flank, F. Mauri. Physical Review B 66, (2002) |
[page 33]
The single particle description of X-ray absorption works well for all K edges and a range of dedicated computer codes exist to calculate the X-ray absorption cross-section. The review of John Rehr in this issue deals with the latest developments in the single electron codes using multiple scattering [1,2]. Cabaret and co-workers describe the new developments in band structure codes and the recently developed PARATEC-based projection method promises to set a new standard for single electron XANES calculations [3]. Applying these one-electron codes (where one-electron applies to a one-electron core excitation, not to the treatment of the valence electrons) to systems such as transition metal oxides one finds excellent agreement for the metal and oxygen K edges, whereas for the other edges, in particular the metal L2,3 edges, the agreement is poor. The reason for this discrepancy is not that the density-of-states is calculated wrongly, but that one does not observe the density of states in such X-ray absorption processes. The reason for the deviation from the density-of-states is the strong overlap of the core wave function with the valence wave functions. The overlap of core and valence wave functions is present also in the ground state, but because all core states are filled, it is not effective and one can approximate the core electrons with their charge. In the final state of an X-ray absorption process one finds a partly filled core state, for example, a 2p5 configuration. In case one studies a system with a partly filled 3d-band, for example, NiO, the final state will have an incompletely filled 3d-band. For NiO this can be approximated as a 3d9 configuration. The 2p-hole and the 3d-hole have radial wave functions that overlap significantly. This wave function overlap is an atomic effect that can be very large. It creates final states that are found after the vector coupling of the 2p and 3d wave functions. [...] This implies that the atomic multiplet effects are of the same order of magnitude in atoms and in solids. [...] In case of s core holes, multiplet effects are effectively reduced to just the exchange interaction between the spin of the s core hole and the spin of the valence electrons. The 1s core states have in all cases a very small exchange interaction, implying that multiplet effects will not be visible. This implies that single electron codes will be effective for all K edges ([...]). [page 34] For multiplet effects to have a significant effect on the mixing of the L3 and L2 edges, the value of the Slater–Condon parameters must be at least of the same order of magnitude as the spin–orbit coupling separating the two edges. [1] J.J. Rehr, R.C. Albers, Rev. Modern Phys. 72 (2000) 621. [2] J.J. Rehr, A.L. Ankudinov, J. Synchrotron Radiat. 8 (2001) 61. [3] M. Taillefumier, D. Cabaret, A.M. Flank, F. Mauri, Phys. Rev. B (2002) 66, art. no. 195107. |
Konservative Bewertung als Bauernopfer: Quelle wird auf Seite 35 als Leseempfehlung genannt:
[59] F. M. F. de Groot. Coordination Chemistry Reviews 249, 31 (2005) |
| [4.] Analyse:Efa/Fragment 035 01 |
| BauernOpfer |
|---|
| Untersuchte Arbeit: Seite: 35, Zeilen: 1-4 |
Quelle: de Groot 2005 Seite(n): 34, Zeilen: - |
|---|---|
| [For multiplet] effects to have a significant effect on the mixing of the L3 and L2 edges, the value of the Slater–Condon parameters must be at least of the same order of magnitude as the spin–orbit coupling separating the two edges. If the core spin–orbit coupling is large, there still can be an effect from the Slater–Condon parameters. For more details discussion about the multiplet effects in x-ray spectroscopy, I recommend for the reader the review paper of Frank de Groot [59].
[59] F. M. F. de Groot. Coordination Chemistry Reviews 249, 31 (2005) |
For multiplet effects to have a significant effect on the mixing of the L3 and L2 edges, the value of the Slater–Condon parameters must be at least of the same order of magnitude as the spin–orbit coupling separating the two edges. If the core spin–orbit coupling is large, there still can be an effect from the Slater–Condon parameters. |
|
006[]
| [1.] Quelle:Efa/de Groot 2005 |
| Autor | Frank de Groot |
| Titel | Multiplet effects in X-ray spectroscopy |
| Zeitschrift | Coordination Chemistry Reviews |
| Datum | January 2005 |
| Jahrgang | 249 |
| Nummer | 1–2 |
| Seiten | 31-63 |
| DOI | https://doi.org/10.1016/j.ccr.2004.03.018 |
| URL | https://anorg.chem.uu.nl/people/staff/FrankdeGroot/pub/141%2005%20degroot%20ccr.pdf |
Literaturverz. |
yes |
| Fußnoten | yes |
| [2.] Quelle:Efa/Chen 1997 |
| Autor | Jingguang G. Chen |
| Titel | NEXAFS investigations of transition metal oxides, nitrides, carbides, sulfides and other interstitial compounds |
| Zeitschrift | Surface Science Reports |
| Jahr | 1997 |
| Jahrgang | 30 |
| Nummer | 1–3 |
| Seiten | 1-152 |
| DOI | https://doi.org/10.1016/S0167-5729(97)00011-3 |
| URL | https://www.sciencedirect.com/science/article/abs/pii/S0167572997000113 |
Literaturverz. |
yes |
| Fußnoten | yes |
| [3.] Quelle:Efa/Foresman Frisch 1996 |
| Autor | James B. Foresman / Æleen Frisch |
| Titel | Exploring Chemistry with Electronic Structure Methods |
| Ort | Pittsburgh, PA |
| Verlag | Gaussian, Inc. |
| Ausgabe | Second Edition |
| Jahr | 1996 |
| URL | http://blogs.cimav.edu.mx/daniel.glossman/data/files/Libros/Exploring%20Chemistry%20With%20Electronic%20Structure%20Methods.pdf |
Literaturverz. |
no |
| Fußnoten | no |