Probing Molecular Dynamics at Attosecond Resolution with Femtosecond Laser Pulses

The kinetic energy distribution of D$^+$ ions resulting from the interaction of a femtosecond laser pulse with D$_2$ molecules is calculated based on the rescattering model. From analyzing the molecular dynamics, it is shown that the recollision time between the ionized electron and the D$_2^+$ ion can be read from the D$^+$ kinetic energy peaks to attosecond accuracy. We further suggest that more precise reading of the clock can be achieved by using shorter fs laser pulses (about 15fs).