Effective Shell-Model interactions for $^{18}$F from the No-Core Shell Model

Insight gained from projected No Core Shell Model calculations in the p-shell can now be utilized to obtain information about and to construct effective Shell Model two-body matrix elements (TBMEs) for heavier nuclei. Here we report on a NCSM investigation in $6 \hbar \Omega$ model space for $^{18}$F in order to determine effective TBMEs for the sd-shell. These matrix elements accurately account for the many-body correlations present in the original large space and can be compared to the empirical (or theoretical) TBMEs employed in a traditional core shell-model calculation. Results for other effective operators, specifically electromagnetic, will also be presented.