Laser-induced Coulomb explosion, geometry modification and reorientation of carbon dioxide

The Coulomb explosion of carbon dioxide in a 55 fs laser pulse of intensity 1.5-3 × 10 16 W cm -2 has been studied using a variety of techniques based on time-of-flight mass spectroscopy. Covariance mapping has been used to identify Coulomb explosion channels and to measure the associated kinetic energy release. By comparing time-of-flight spectra taken with linearly and circularly polarized light, a clear signature of laser-induced reorientation is found, which is strongest for the lowest Coulombic channel. Ion-momentum imaging coupled with Monte Carlo simulation shows that the zero-point bend-angle distribution is better preserved than for longer laser pulses. However, some residue of the sequential processes dominant in much longer pulses is found.