CCC Theory A.Kheifets JPB 34, L247 (2001) energy above thresholds (eV) Electron-scatteringShake-Off.

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CCC Theory A.Kheifets JPB 34, L247 (2001) energy above thresholds (eV) Electron-scatteringShake-Off

simple: overlap He (r 1,r 2 )| He { + } (r 1 )> Photoabsorbtion-> r 2 =0 Compton Scattering-> sr 2

Fazit: Wirkungsquerschnitte ok. Wellenfunktion für r 1 =0 und s r 1 ok Winkelverteilungen shake off??? Was ist dran an den einfachen Bildern?

What can we learn about the initial state by (,2e)? ground state How does 1 photon talk to 2 electrons? QM three body problem

CCC Theory A.Kheifets JPB 34, L247 (2001) energy above thresholds (eV) Electron-scatteringShake-Off

Electron-scattering Shake-Off 1)is the 2 step picture ok? can we experimentally tell which electron absorbed the photo? 2) what is the second step: shake or electron-scattering

Two Step Model: 1. Step: Absorbtion of Photon Energy and angular momentum is given to one electron 2. Step: shake or electron scattering?

Electron-scatteringShake-Off 90 o 1eV 449eV420eV 30eV

ground state reaction mechanisms Quantum- few-body problem Hohe Energie -> Endzustand spielt kaum Rolle Niedrige Energien : 3 Teilchen Problem!

Quantum- few-body problem December 1999 T. Rescigno, B. McCurdy

single ionization k r =-k e double ionization k r =-(k 1 +k 2 ) Polarization electron = ion electron 1 ion

Two Step Modell double ionization k r =-(k 1 +k 2 ) Polarization electron 1 ion 1) absorbtion by charge dipole nucleus keeps memory of first step 2) e-e interaction shake or interception nucleus is spectator

2 electrons escaping from the potential of the He 2+ k 1,k 2 k1k1 k2k2 ion Electron energy distribution He 2+ nucleus in the 2 center potential of the electron pair Jacobi coordinates (Feagin & Briggs) k r =k ion =(k 1 +k 2 ) k R =1/2(k 1 -k 2 ) k ion =(k 1 +k 2 ) ion (cm saddle) energy & breakup energy of electron pair Nützlichkeit von klug gewählten Koordinaten:

Energy distribution of ionic motion on saddle k R =1/2(k 1 -k 2 ) k ion = (k 1 +k 2 ) Relative motion of electron pair

1 20 80 eV Ionic motion Pont &Shakeshaft (absolute scale!) J. Feagin 4 th order Wannier Freezing out of ions on Wannier saddle k R =1/2(k 1 -k 2 )

He 2+ nucleus momentum k r =k 1 +k 2 k R =1/2(k 1 -k 2 )

He 2+ nucleus momentum k r =k 1 +k 2 k R =1/2(k 1 -k 2 )

2 electrons escaping from the potential of the He 2+ k 1,k 2 k1k1 k2k2 ion Electron energy distribution He 2+ nucleus in the 2 center potential of the electron pair Jacobi coordinates (Feagin & Briggs) k r =k ion =(k 1 +k 2 ) k R =1/2(k 1 -k 2 ) k ion =(k 1 +k 2 ) ion (cm saddle) energy & breakup energy of electron pair Nützlichkeit von klug gewählten Koordinaten:

e2e2 Direction of e 1 Image of | (k 1,k 2 )| 2

e2e2 Direction of e 1 He 25 eV electron 1 Image of | (k 1,k 2 )| 2

He 25 eV electron 1 selection rule: 1 P o two particle wave function: k 1 =- k 2 forbidden! Electron repulsion: never to same half plane

99eV h + He He 2+ + 2e - e2e2 E e1 =E e2 Polarization e1e1

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