Interatomic Coulombic decay following photoionization of the helium dimer: observation of vibrational structure.
Using synchrotron radiation we simultaneously ionize and excite one helium atom of a helium dimer (He2) in a shakeup process. The populated states of the dimer ion [i.e., He(*+)(n = 2, 3) - He] are found to deexcite via interatomic Coulombic decay. This leads to the emission of a second electron from the neutral site and a subsequent Coulomb explosion. In this Letter we present a measurement of the momenta of fragments that are created during this reaction. The electron energy distribution and the kinetic energy release of the two He+ ions show pronounced oscillations which we attribute to the structure of the vibrational wave function of the dimer ion.
Havermeier
T
T
Institut für Kernphysik, J. W. Goethe Universität, Max-von-Laue-Strasse 1, 60438 Frankfurt, Germany.
Jahnke
T
T
Kreidi
K
K
Wallauer
R
R
Voss
S
S
Schöffler
M
M
Schössler
S
S
Foucar
L
L
Neumann
N
N
Titze
J
J
Sann
H
H
Kühnel
M
M
Voigtsberger
J
J
Morilla
J H
JH
Schöllkopf
W
W
Schmidt-Böcking
H
H
Grisenti
R E
RE
Dörner
R
R