  In this work, we have studied the isovector giant dipole resonance (IVGDR) in
even-even Sm isotopes within time-dependent Hartree-Fock (TDHF) with four
Skyrme forces SLy6, SVbas, SLy5 and UNEDF1. The approach we have followed is
somewhat similar to the one we did in our previous work in the region of
Neodymium (Nd, Z=60)
[\href{https://iopscience.iop.org/article/10.1088/1402-4896/ab73d8}{Physica
Scripta (2020)}]. We have calculated the dipole strength of $
^{128-164}\text{Sm}$, and compared with the available experimental data. An
overall agreement between them is obtained. The dipole strength in
neutron-deficient $ ^{128-142}\text{Sm}$ and in neutron-rich
$^{156-164}\text{Sm}$ isotopes are predicted. Shape phase transition as well as
shape coexistence in Sm isotopes are also investigated in the light of IVGDR.
In addition, the correlation between the quadrupole deformation parameter
$\beta_{2}$ and the splitting $\Delta E/ \bar{E}_{m}$ of the giant dipole
resonance (GDR) spectra is studied. The results confirm that $\Delta E/
\bar{E}_{m}$ is proportional to quadrupole deformation $\beta_{2}$
