  Coherent control of internal conversion (IC) between the first ($S_1$) and
second ($S_2$) singlet excited electronic states in pyrazine, where the $S_2$
state is populated from the ground singlet electronic state $S_0$ by weak field
excitation, is examined. Control is implemented by shaping the laser which
excites $S_2$. Excitation and IC are considered simultaneously, using the
recently introduced resonance-based control approach. Highly successful control
is achieved by optimizing both the amplitude and phase profiles of the laser
spectrum. The dependence of control on the properties of resonances in $S_2$ is
demonstrated.
