*2.2. Semi-Phenomenological Approaches*

A first step towards a more theoretical framework was to use a more realistic form of *V*ˆ CD on top of phenomenological wave functions. This was introduced in Ref. [16] for the *sd* shell but found to be less successful than a purely phenomenological charge-dependent term. More recently, in Ref. [33], microscopic charge-independence breaking *p f*-shell Hamiltonians have been constructed from the two-body CD-Bonn, Argonne *v*<sup>18</sup> and chiral N3LO (next-to-next-to-next-to-leading order) potentials on top of the phenomenological GXPF1A interaction. The authors compared theoretical IMME *c* coefficients as a function of the angular momentum in selected *p f*-shell nuclei with experimental data and conclude that the theory indicates too-strong of a contribution of the charge-independence breaking terms of nuclear origin.
