  We study the structure of the no-core shell model wave functions for $^6$Li
and $^{12}$C by investigating the ground state and first excited state electron
scattering charge form factors. In both nuclei, large particle-hole ($ph$)
amplitudes in the wave functions appear with the opposite sign to that needed
to reproduce the shape of the $(e,e')$ form factors, the charge radii, and the
B(E2) values for the lowest two states. The difference in sign appears to arise
mainly from the monopole $\Delta\hbar\omega=2$ matrix elements of the kinetic
and potential energy (T+V) that transform under the harmonic oscillator SU(3)
symmetries as $(\lambda,\mu)=(2,0)$. These are difficult to determine
self-consistently, but they have a strong effect on the structure of the
low-lying states and on the giant monopole and quadrupole resonances. The
Lee-Suzuki transformation, used to account for the restricted nature of the
space in terms of an effective interaction, introduces large higher-order
$\Delta\hbar\omega=n, n>$2, $ph$ amplitudes in the wave functions. The latter
$ph$ excitations aggravate the disagreement between the experimental and
predicted $(e,e')$ form factors with increasing model spaces, especially at
high momentum transfers. For sufficiently large model spaces the situation
begins to resolve itself for $^6$Li, but the convergence is slow. A
prescription to constrain the $ph$ excitations would likely accelerate
convergence of the calculations.
