The higher Tamm-Dancoff Approximation (HTDA) is extended to include vibrational correlations
with or without pairing correlations. The residual interaction in use is of the delta (in the T=1 channel) plus
multipole-multipole type. In this paper we have limited our study to the mere case of isoscalar quadrupole
correlations. The approach is illustrated by the consideration of ground state and isoscalar giant quadrupole
resonance properties in the Ca40 nucleus. ?? 2010 The American Physical Society
