The computed parallel and perpendicular components of magnetic HFS constant of 87 Sr in SrF are presented in Table . The relative deviations of the computed values from the experimental results are shown in Fig. and Fig. , which imply that the results at basis G are more accurate than those at other basis sets. The HFS constants obtained from the DHF method slightly decreases as the basis set size increases from the double-zeta basis to the triple-zeta basis whereas the results computed by the correlated methods increases significantly. We expect that a further increase in the basis set size to the quadruple-zeta basis would further improve the HFS results as shown in Ref. . Additionally, the correlated results of the HFS constants monotonically increases, as expected, with the addition of high-energy virtual functions (i.e., as one moves from basis A to basis E) as it allows proper correlation of the core-electrons . One should note here that the expectation-value results for the HFS constant of 87 Sr are always larger than the corresponding Z-vector results at all the considered bases. In other words, the expectation-value results are in better agreement with the experimental value than the corresponding Z-vector values.