What experiment was that?
Observation of a nearly isotropic, high-energy Coulomb explosion group
in the fragmentation of D2 by short laser pulses
A. Staudte,1 C. L. Cocke,2 M. H. Prior,3 A. Belkacem,3 C. Ray,3 H. W. Chong,3 T. E. Glover,3 R. W. Schoenlein,3
1Institut fu¨r Kernphysik, University of Frankfurt, Frankfurt, Germany
2Physics Department, Kansas State University, Manhattan, Kansas 66506-2601
3Lawrence Berkeley Laboratory, Berkeley, California 94720
4Max-Planck-Institut fu¨r Physik Komplexer Systeme, No¨thnitzer Strasse 38, 01187 Dresden, Germany
~Received 12 September 2001; published 18 January 2002
We have used momentum spectroscopy to examine the production of deuteron pairs in the double ionization
of D2 molecules by a fast (200 fs), moderately intense (0.65– 8.0)x1014 W/cm2 laser pulses. By measuring
in coincidence the momentum vectors of both deuterons, we have isolated, at the lowest laser power
density, a weak ionization channel characterized by Coulomb-explosion deuterons with a sum energy near 10
eV. This is much higher than has been seen in previous studies. The angular distribution of these deuterons is
nearly isotropic, in contrast to previous observations that the deuterons are strongly peaked along the laser
polarization. These new observations suggest a previously unobserved ionization mechanism.
PHYSICAL REVIEW A, VOLUME 65, 020703~R!