Born Oppenheimer Näherung

Präsentation zum Thema: "Born Oppenheimer Näherung"—  Präsentation transkript:

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2 Born Oppenheimer Näherung
re Rpp(Kernabstand) Kernwellenfunktion Elektronische Wellenfunktion R nur Parameter Potential Wie sieht die Wellenfunktion dazu aus? Näherung: Harmonischer Oszillator

3 Measure the internuclear distance: Reflection Approximation
harmonic oszillator Morse Potential

4 h Elektronenenergie E CO 1.13 Å 1.08 Å CO+(C1s) 300meV

5 O C Molecular Innershell Photoionization – fixed in space molecules
Polarization e- from K-shell, 10eV Energy h = 295 eV C O molecular orientation measurement

6 Molecular Innershell Photoionization – fixed in space molecules
h = 295 eV Photoelectron (10eV) C O C O Auger Electron 250 eV C O CO2+ + C O CO2+ +

7 CO: Carbon K-Ionization
Detector Dead Time (10nsec) Electric field

8 2 1+ (B-State) From: Kerkau and Schmidt
CO eV photon CO+ ground state Photoelectron Auger Electron CO2+ Franck-Condon for C-K Hole C+(2P)+O+(4S) 2 1+ (B-State) From: Kerkau and Schmidt

9 Axial Recoil Approximation: is the Fragmentation faster
than Rotation?

10 Identical fit !

11 distribution of rotation angle
50deg O C random rotation with exponential distribution of rotation angle

12 distribution of rotation angle
50deg O C random rotation with exponential distribution of rotation angle

13 femto second clock HC+ Acetylene HCCH Vinylidene C+ H2C+ Osipov et al PRL 90(2003)233002

14 <60 fsec Isomerization Time? Osipov et al PRL 90(2003)233002
0.35 rad Mean angle of rotation Fit randomly rotated A pattern to V measurements • <60 fsec Isomerization Time? Osipov et al PRL 90(2003)233002 Physics Today Aug.2003 p 19ff

15 h O C He + 99eV -> He1+(1S) + e- Interference between different
Polarization Interference between different classical paths (diffraction pattern) h O C

16 + L = 1 (within dipole approximation)
He + 99eV -> He1+(1S) + e- Polarization Interference between different classical paths (diffraction pattern) L = 1 (within dipole approximation) Entangled State of rotating Molecule and Electron + h O C h = 295 eV

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18 O C h O C h

19 O C h O C h

20 Chirality in Nonmagnetic Systems?
initial state final Chiral many body, intial states oriented molecules Theoretical Prediction: Dubs, McCoy PRL 45 (1985) Pioneering Experiment: Circular Dichroism CO on surface Schönhense et al

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22 1.3 eV 10 eV 25 eV Multiple Scattering Theory: R. Diez Muino, M.van Hove, D. Rolles, C. Fadley, F. Garcia de Abajo

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24 Circular light measures PHASE SHIFTS (parallel/perp)
Circular Dichroism from Aligned Molecules? 9 eV K-Shell N2 Circular light measures PHASE SHIFTS (parallel/perp) Jahnke et al, PRL 88(2002)073002

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27 Zwischen Atomen und Molekülen:
van der Vaals Cluster

28 Inter Atomic Coulombic Decay
Wie können Atome innere Energie abgeben? Beeinflußt die Umgebung die Eigenschaften des Atoms?

29 Decay processes of electronically excited particles:
Pierre Auger 1925 Flourescence decay Auger decay Energy 1s1s 2s2p

30 Decay processes of electronically excited particles:
Flourescence decay Auger decay Inter Atomic Coulombic Decay (ICD) (L. Cederbaum et al. PRL 79,4778(1997) ICD electron from neighbor atom energy transfer virtual photon exchange

31 Where? van der Vaals Cluster Hydrogen bonded systems Liquids

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33 Neon - Dimer 3.1 A Binding energy Ne2 1.5 meV van der Vaals Force

34 3.1 A Neon - Dimer Ne+ Ne Auger decay energetically forbidden
1s 2s 2p Ne+ 1s 2s 2p Ne Auger decay energetically forbidden from Ne+(2s-1) - 11eV energy transfer virtual photon exchange

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36 Ne+

37 single photon below Ne2+ threshold
Till Jahnke, et al. PRL 93, (2004)

38 Ne+ Ne+ Kinetic Energy Release (eV)
electron energy (eV) Ne+ 2s Photoelectron 5eV Energy of Ne2(2s-1) ICD electron

39 Ne+ Ne+ h=59 eV Ne+ Ne2 Photo- electron 10eV ICD e- KER Santra et al.
PRL 85, (2000) Ne2 Ne+ Ne+ Ne+ Ne2(2s-1)+ ICD e- KER

40 Ne+ Ne+ Kinetic Energy Release (eV)
Ne2(2s-1)+ Photo- electron 10eV h=59 eV Ne+ Ne+ ICD e- KER Ne+ Ne+ Kinetic Energy Release (eV) electron energy (eV)

41 Ne+ Ne+ Kinetic Energy Release (eV)
Santra et al PRL 85,4490(2000) Ne+ Ne+ Ne2+(2s-1) Photo-e- ICD ICD-e- Ne+ Ne+ Kinetic Energy Release (eV) electron energy (eV) KER

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43 e- A e- - I - + 1899 J.J. Thomson 1900 Elster & Gütel 1900 Lenard
monochromatic light e- e- A - max. electron energy independent of intensity I high intensity low intensity - + Potential

44 “BIG Photon” E>Ebind
Energy 24.6 eV eV 79 eV “BIG Photon” E>Ebind

45 Energy 24.6 eV eV 79 eV “Small Photon” 1.5eV (800nm)

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47 Energy 1015 W/cm2 24.6 eV eV 79 eV 53 photons @800 nm

48 Viele interessante Fragen:
Extrem nichtlineare Prozesse von Störungstheorie (Elektronische)Materie unter extremen Bedingungen Extrem kurz Zeiten “Attosekunden” “Elektronenbewegung sichbar machen”

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50 Räumliche Kompression: 5 cm Brenweite: 5mm -> 5 um focus
Ziel: W/cm2 ????? Laser: 1 W, 800nm Faktor 106 Räumliche Kompression: 5 cm Brenweite: 5mm -> 5 um focus Zeitliche Kompression: 1kHz, 220 fsec (10-15) Faktor 1010 100um 50 um 5um

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52 Lichtgeschosse: 3*3*3 m3 30 ... 6 femto Sekunden Lichtgeschwindigkeit
Leistungsdichte 1016W/cm2 0.2 milli Joule GeV 2*1015 Photonen (a 1.5 eV) Elektrische Felder > 1011 V/m Photo: S.Voss

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54 Peak Power <1016W/cm2 Standard “Strong Field”
Laser (Ti Sa): fsec Atom: Helium 1010 Photons Field (1016 W/cm2) V/m Field V/m 2.5 fsec (800nm) 0.15 fsec <tu>