progenitor mass and explosion energy make a poor candidate for probing supernova explosion energy. We note that the production site trends in more closely resemble those of . However, the overall production of decreases with higher mass progenitors while shows no such pattern. Similar to , is primarily produced in the decay of another isotope; in this case, .

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In contrast to the above, for we do not see strong trends in final yields with explosion energy. Production primarily occurs in the innermost ejecta; the core (Si-shell) and the C/O shell. Similar to , as the progenitor mass and explosion energy increases, production occurs further out into the burning layers, up to the outer end of the C/O shell. As we discussed in section \[sec:probestruct\], is primarily produced in the innermost ejecta and is not produced in the He shell.

does demonstrate changes in abundance by mass coordinate with explosion energy, but the abundances are not a clear function of explosion energy. However, we also note the decrease in production with increasing progenitor mass, as shown in Figure \[fig:yield\_vexp\]. As this isotope is primarily made in the interior, the greater fall-back in the higher mass progenitors leads to a 