  The molecular dipole moment and magnetic hyperfine structure constant demand
an accurate wavefunction far from the nucleus and in near nuclear region,
respectively. We, therefore, employ the so-called Z-vector method in the domain
of relativistic coupled cluster theory to calculate the first order property of
molecular systems in their open-shell ground state configuration. The
implemented method is applied to calculate molecular dipole moment and parallel
component of the magnetic hyperfine structure constant of SrF molecule. The
results of our calculation are compared with the experimental and other
available theoretically calculated values. We are successful in achieving good
accordance with the experimental results. The result of our calculation of
molecular dipole moment is in the accuracy of ~? 0.5 %, which is clearly an
improvement over the previous calculation based on the expectation value method
in the four component coupled cluster framework [V. S. Prasannaa et al, Phys.
Rev. A 90, 052507 (2014)] and it is the best calculated value till date. Thus,
it can be inferred that the Z vector method can provide an accurate
wavefunction in both near and far nuclear region, which is evident from our
calculated results.
