Fig. 1.

Attosecond control of the excitation and ionization pathways of D₂ on short timescales. (Right) Simplified potential energy surfaces of the D₂ and . The purple and red arrows represent the VUV harmonics and IR photons used to coherently control the populations of the excited neutral and ion states in the Franck–Condon region through two-pathway quantum interference of electronic wave packets in B, B* (single photon) and EF (two photon) states. (Lower Left) Calculated excitation probabilities into states of Σ_u and Σ_g symmetries of neutral H₂ (dominated, respectively, by the B and EF states) as a function of time delay. The blue lobes, plotted on the right of the panel, are sketches of the Σ_u and Σ_g orbitals representing the excited electron dynamics. Theoretical predictions show that the electronically excited populations can be switched between the even B and odd parity EF potentials on attosecond timescales, which can in turn control how the molecule vibrates. (Upper Left) The experimental photoelectron and D⁺ yields modulate on full and half-cycle attosecond timescales, as the delay between the pump VUV + IR and control IR pulses is scanned.