  Results of a comprehensive shell model (SM) analyses, within the full
$f_{5/2}pg_{9/2}$ model space, of the recently available experimental data [P.
Ruotsalainen et al., Phy. Rec. C {88}, 024320 (2013)] with four $T=0$ bands and
one $T=1$ band in the odd-odd $N=Z$ nucleus $^{66}$As are presented. The
calculations are performed using jj44b effective interaction developed recently
by B.A. Brown and A.F. Lisetskiy for this model space. For the lowest two $T=0$
bands and the $T=1$ band, the results are in reasonable agreement with
experimental data and deformed shell model is used to identify their intrinsic
structure. For the $T=1$ band, structural change at $8^+$ is predicted. For the
third $9^+$ band with $T=0$, the shell model $B(E2)$ values and quadrupole
moments (in addition to energies) are consistent with the interpretation in
terms of aligned isoscalar $np$ pair in $g_{9/2}$ orbit coupled to the
$^{64}$Ge ground band. Similarly, the $9^+$ level of band 4 and a close lying
$5^+$ level are found to be isomeric states in the analysis. Finally, energies
of the band 5 members calculated using shell model with both positive and
negative parity show that the observed levels are most likely negative parity
levels. The SM results with jj44b are also compared with the results obtained
using JUN45 interaction.
