Recoil-ion momentum distributions for two-photon double ionization of He and Ne by 44 eV free-electron laser radiation.
Recoil-ion momentum distributions for two-photon double ionization of He and Ne (variant Planck's over omega=44 eV) have been recorded with a reaction microscope at FLASH (the free-electron laser at Hamburg) at an intensity of approximately 1 x 10(14) W/cm2 exploring the dynamics of the two fundamental two-photon-two-electron reaction pathways, namely, sequential and direct (or nonsequential) absorption of the photons. We find strong differences in the recoil-ion momentum patterns for the two mechanisms pointing to the significantly different two-electron emission dynamics and thus provide serious constraints for theoretical models.
Rudenko
A
A
Max-Planck Advanced Study Group at CFEL, Notkestrasse 85, 22607 Hamburg, Germany.
Foucar
L
L
Kurka
M
M
Ergler
Th
T
Kühnel
K U
KU
Jiang
Y H
YH
Voitkiv
A
A
Najjari
B
B
Kheifets
A
A
Lüdemann
S
S
Havermeier
T
T
Smolarski
M
M
Schössler
S
S
Cole
K
K
Schöffler
M
M
Dörner
R
R
Düsterer
S
S
Li
W
W
Keitel
B
B
Treusch
R
R
Gensch
M
M
Schröter
C D
CD
Moshammer
R
R
Ullrich
J
J