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7. WocheQuasikristalleW. Steurer Zeitplan 1.-4. WocheIonenkristalle Perowskit kovalente anorganische Verbindungen Zeolithe DLS (Geometrie optimierung)

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Präsentation zum Thema: "7. WocheQuasikristalleW. Steurer Zeitplan 1.-4. WocheIonenkristalle Perowskit kovalente anorganische Verbindungen Zeolithe DLS (Geometrie optimierung)"—  Präsentation transkript:

1 7. WocheQuasikristalleW. Steurer Zeitplan WocheIonenkristalle Perowskit kovalente anorganische Verbindungen Zeolithe DLS (Geometrie optimierung) intermetallische Verbindungen WochePulverdiffraktometrie Wocheorganische Kristallchemie und B. Schweizer Strukturdatenbanken Anorganische Kristallchemie

2 Kristallchemie und Kristallstrukturdatenbanken Pulverdiffraktometrie Einkristall Strukturanalyse Strukturanalyse mittels Pulverdaten Kristallchemie in der Strukturanalyse Modellbau Simulated annealing Evolutionäre Algorithmen FOCUS Charge flipping

3 3-dimensionale, 4-fach verknüpfte Gerüststruktur FOCUS Zeolithe

4 Zeolithe Eckenverknüpfte TO 4 Tetraeder FOCUS

5 O-Si-O 109.5˚ Si-O-Si 145˚ bekannte T-O Bindungslängen, O-T-O und T-O-T Winkel Si-O 1.61 Å FOCUS Zeolithe 3-dimensionale, 4-fach verknüpfte Gerüststruktur Eckenverknüpfte TO 4 Tetraeder

6 convergence? framework search yesno FOCUS approximate unit cell contents individual minimum distances selected reflection intensities electron density mappeak search assignment of atoms by peak height minimum distances assignment of atoms to largest fragment new phase set starting phases framework classification histogram

7 FOCUS approximate unit cell contents individual minimum distances selected reflection intensities AlPO-ZON a Å b Å c Å RaumgruppePbca Chemische Zusammensetzung|(RF) x |[Al 32 P 32 O 128 ] Al - Al Al - P P - P V = 3956 Å 3 16 T-Atome pro 1000 Å 3 Al - O P - O 3.1 Å 2.7 Å 2.6 Å 1.4 Å 2.3 Å 1.6 Å O - O

8 AlPO-ZON a = Å, b = Å, c = Å Pbca

9 convergence? framework search yesno FOCUS approximate unit cell contents individual minimum distances selected reflection intensities electron density mappeak search assignment of atoms by peak height minimum distances assignment of atoms to largest fragment new phase set starting phases framework classification histogram

10 Peak-Positionen und -Höhen

11 convergence? framework search yesno FOCUS approximate unit cell contents individual minimum distances selected reflection intensities electron density mappeak search assignment of atoms by peak height minimum distances assignment of atoms to largest fragment new phase set starting phases framework classification histogram

12 Atome durch Peakhöhe und miminale Abstände zugeordnet

13 convergence? framework search yesno FOCUS approximate unit cell contents individual minimum distances selected reflection intensities electron density mappeak search assignment of atoms by peak height minimum distances assignment of atoms to largest fragment new phase set starting phases framework classification histogram

14 Atome durch grösstes Fragment zugeordnet

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16 new phase set assignment of atoms by peak height minimum distances assignment of atoms to largest fragment Elektronendichte Strukturfaktor Streufaktor berechnete Phasen gemessene Amplituden

17 convergence? framework search yesno FOCUS approximate unit cell contents individual minimum distances selected reflection intensities electron density mappeak search assignment of atoms by peak height minimum distances assignment of atoms to largest fragment new phase set starting phases framework classification histogram

18 Gerüst-Klassifikation Wie kann man ein Gerüst eindeutig erkennen? Coordination sequence Loop configuration Vertex symbol · 4 · 4 · 6 · 6 · 12

19 Elementarzelle RaumgruppeP P4 2 /ncm a Å Å c Å Å P41212P41212P41212P41212 VPI-9 Chemische Zusammensetzung OriginalK 4 Rb 20 [Si 48 Zn 12 O 120 ] 64H 2 O NH 4 -ausgetauscht(NH 4 ) 24 [Si 48 Zn 12 O 120 ] 64H 2 O DatenOriginalNH 4 -ausgetauscht SynchrotronSNBL an ESRFSNBL an ESRF Wellenlänge Å Å Å

20 VPI-9 - FOCUS Input RaumgruppeP4 2 /ncm Elementarzellea Å b Å Atome / EZZn (4-fach verknüpft)1212 Si (4-fach verknüpft)4448 O (brückend) minimale AbständeZn - O1.7 ÅZn - Si2.9 Å Si - O1.5 ÅZn - Zn4.0 Å O - O2.3 ÅSi - Si2.9 Å Reflexe258 Gerüst-Typen gefunden (übernacht)1356 (ein Typ 102 Mal gefunden) (ein Typ 102 Mal gefunden)

21 Histogramm der Gerüst-Typen Gerüst-Typen wahrscheinlichster Gerüst-Typ

22 VPI-9 Gerüststruktur mit 7 (Si,Zn) pro asymmetrische Einheit

23 Rubidium Zinkosilikat VPI-9 12 Si, 3 Zn, 30 O, 9 Rb, 2 K und 3 H 2 O pro asymmetrische Einheit VPI-9

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25 Kristallchemie und Kristallstrukturdatenbanken Pulverdiffraktometrie Einkristall Strukturanalyse Strukturanalyse mittels Pulverdaten Kristallchemie in der Strukturanalyse Modellbau Simulated annealing Evolutionäre Algorithmen FOCUS Charge flipping

26 assign random phases flip sign of ed < flip sign of ed < Fourier transform R-value (|F hkl (calc)| vs |F hkl (obs)| combine |F hkl (obs)| with hkl (calc) hkl (calc) Charge Flipping |F hkl (obs)| (ed threshold for flipping) phase shifts for weak reflections? electron density map perturbed electron density map |F hkl (calc)| hkl (calc) Oszlányi, G. and Sütõ, A. (2004). Acta Cryst. A60, Oszlányi, G. and Sütõ, A. (2005). Acta Cryst. A61,

27 |F hkl (obs)| (ed threshold for flipping) phase shifts for weak reflections? |F hkl (obs)| with overlap groups (ed threshold for flipping) phase shifts for weak reflections? repartitioning after n cycles electron density histogram assign random phases flip sign of ed < flip sign of ed < Fourier transform R-value combine |F hkl (obs)| with hkl (calc) hkl (calc) electron density map perturbed electron density map |F hkl (calc)| hkl (calc) yesno histogram matching modified electron density map Fourier transform |F hkl (calc)| hkl (calc) repartitionoverlappingreflections new|F hkl (obs)| n cycles? Charge Flipping (powder)

28 12 Å 8 Å 5 Å Electronendichte alle ¼ Å alle ¼ Å 48 x 32 x 20 = points = points Histogram matching

29 Elektronendichte Werte nach Intensität ordnen Liste in 50 Bereiche aufteilen Durchschnittsdichte pro Bereich rechnen typischer Zeolith Karte nach ein paar Zyklen Charge Flipping

30 Powder Charge Flipping [Zr 12 P 16 O 60 (OH) 4 F 8 ]

31 Powder Charge Flipping [Zr 12 P 16 O 60 (OH) 4 F 8 ]

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