Counterintuitive alignment of H2(+) in intense femtosecond laser fields.
The multiphoton ionization of H2 has been studied using laser pulses of 266 nm wavelength, 250 fs duration, and 5x10(13) W/cm(2) peak intensity. Dissociation of H2(+) via one-photon absorption proceeds through two channels with markedly different proton angular distributions. The lower-energy channel (2.6 eV kinetic energy release) is produced in the bond softening mechanism, which generates parallel alignment. The higher-energy channel (3.5 eV) originates from population trapping in a light-induced bound state, where bond hardening generates orthogonal, counterintuitive alignment.
Frasinski
L J
LJ
J. J. Thomson Physical Laboratory, The University of Reading, Whiteknights, Reading RG6 6AF, United Kingdom. L.J.Frasinski@reading.ac.uk
Plumridge
J
J
Posthumus
J H
JH
Codling
K
K
Taday
P F
PF
Divall
E J
EJ
Langley
A J
AJ