On laser Coulomb explosion imaging of proton motion

From exact non-Born–Oppenheimer simulations of the dissociative-ionization dynamics of H2+ in an intense (I>1015 W/cm2), ultrashort (tp<5 fs) λ=800 nm laser pulse, one can measure the time evolution of the probability distribution |ψ(R,t)|2 of the initial proton wave packet. It is shown that best imaging is obtained for ultrashort pulses (tp<3 fs) at 4×1015 W/cm2 or much shorter wavelengths, λ⩽30 nm. The relevance of this imaging criterion is discussed in relation to current laser Coulomb explosion imaging of proton transfer in large molecules.