Behaviour of D2 in an intense CO2 laser field

We describe the first investigation of tunnel ionisation and dissociation of D2 in a strong 10 μm laser field. The process begins with the single tunnel ionisation of D2 followed by the subsequent dissociation of the molecular ion and is terminated by a second tunnel ionisation. The fragmentsʹ kinetic energy (KE) and ion yields (D2+ and D+) were measured as a function of the peak intensity. The KE spectrum has two distinguishable maxima corresponding to slow and fast ions. The energy of the slow fragments increases linearly with the laser intensity, whereas the energy of fast fragments is insensitive to this.