  Resonant Raman excitation by ultrafast vacuum ultraviolet laser pulses is a
powerful means to study electron dynamics in molecules, but experiments must
contend with linear background ionization: frequencies high enough to reach
resonant core-valence transitions will usually ionize all occupied orbitals as
well, and the ionization cross sections are usually dominant. Here we show that
attosecond pulses can induce a process, transient impulsive stimulated Raman
scattering, which can overwhelm valence ionization. Calculations are performed
for atomic sodium, but the principal is valid for many molecular systems. This
approach opens the path for high fidelity multidimensional spectroscopy with
attosecond pulses.
