  Time-dependent equation-of-motion coupled cluster (TD-EOM-CC) is used to
simulate impulsive stimulated x-ray Raman scattering (ISXRS) of ultrashort
laser pulses by neon, carbon monoxide, pyrrole, and p-aminophenol. The
TD-EOM-CC equations are expressed in the basis of field-free EOM-CC states,
where the calculation of the core-excited states is simplified through the use
of the core-valence separation (CVS) approximation. The transfer of electronic
population from the ground state to the core- and valence-excited states is
calculated for different numbers of included core- and valence-excited states,
as well as for electric field pulses with different polarizations and carrier
frequencies. The results indicate that Gaussian pulses can transfer significant
electronic populations to the valence states through the Raman process. The
sensitivity of this population transfer to the model parameters is analyzed.
The time-dependent electronic density for p-aminophenol is also showcased,
supporting the interpretation that ISXRS involves localized core excitations
and can be used to rapidly generate valence wavepackets.
