is set to have a value $N^* + \Delta N$ (where $\Delta N$ has only small value such as 1 or 2 or so), it appears that each of the $\Delta N$ atoms go to orbit 2 for which $\Delta I (= I_{N^*+1}- I_{N^*}$) is $\approx$ 6.3$\%$ of the contribution of an atom in orbit 1. Such a small increase can be easily compensated if the contribution to $I_{N^*+1}$ due to each of the $N^*$ atoms in orbit 1 gets reduced by 6.3/$N^*\%$ presumably due to small decrease, $\Delta r$, in the distance of atoms from the axis of rotation of M:$^4$He$_{N^*}$ and this does not demand necessarily a decrease in M-$^4$He bond length; a decrease by $\Delta r$ in the projection of the bond on the plane $\perp$ to the axis of rotation would suffice and this can be estimated to fall around 6.3/2$N^*\%$ of the said projection which equals to $\approx 0.8\%$ if $N^*= 4$, or 0.5$\%$ if $N^* = 6$ or $\approx 0.4\%$ if $N^* = 8$. Such a small change can easily be expected as a possible effect of an atom added to M:$^4$He$_{N^*}$ or another added to M:$^4$He$_{N^*+1}$; this naturally explains the said observation.

\(3) 