  The recently measured experimental data of Legnaro National Laboratories on
neutron rich even isotopes of $^{62-66}$Fe with A=62,64,66 have been
interpreted in the framework of large scale shell model. Calculations have been
performed with a newly derived effective interaction GXPF1A in full $\it{fp}$
space without truncation. The experimental data is very well explained for
$^{62}$Fe, satisfactorily reproduced for $^{64}$Fe and poorly fitted for
$^{66}$Fe. The increasing collectivity reflected in experimental data when
approaching N=40 is not reproduced in calculated values. This indicates that
whereas the considered valence space is adequate for $^{62}$Fe, inclusion of
higher orbits from $\it{sdg}$ shell is required for describing $^{66}$Fe.

Nuclear Theory