We also use these same values in the small space. One can argue that in the small space one should use a renormalized value $\chi'$ which is close to twice $\chi$. However, as mentioned above, the wave function and hence $B(M1)$ and $B(E2)$ will not change, only the energies. By choosing the same $\chi$ in the two spaces it is easier to see what the differences in the two calculations are. The values of $\chi$ are 0.5762 $\frac{MeV}{fm^4}$ for $^8Be$ and 0.3615 $\frac{MeV}{fm^4}$ for $^{10}Be$.

The summed magnetic dipole strength
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In Table I we give the summed magnetic dipole strength ($\sum_i~ B(M1:
0_1^+,~T=1 \rightarrow 1_i^+,~T=1)$ and $\sum_i~ B(M1:
0_1^+,~T=1 \rightarrow 1_i^+,~T=2)$ ) broken up into isoscalar and isovector and spin and orbit and where we use the ($x,y$) interaction with $x=1$, $y=1$. We first discuss the behaviour as a function of the size of the model space. Later we will make a comparison of the behaviour in $^8\mbox{Be}$ and $^{10}\mbox{Be}$. There are striking differences for the two nuclei.

Our small space calculation consists of all configurations of the form $(0s)^4(0p)^4$ for $^8\mbox{Be}$ and $(0s)^4(0p)^6$ for $^{10}\mbox{Be}$. The large space consists of those configurations plus $2\hbar\omega$ excitations. Thus one can 