  We use neutron scattering to study vanadium (hole)-doped LiFe$_{1-x}$V$_x$As.
In the undoped state, LiFeAs exhibits superconductivity at $T_c=18$ K and
transverse incommensurate spin excitations similar to electron overdoped iron
pnictides. Upon vanadium-doping to form LiFe$_{0.955}$V$_{0.045}$, the
transverse incommensurate spin excitations in LiFeAs transform into
longitudinally elongated in a similar fashion as that of potassium (hole) doped
Ba$_{0.7}$K$_{0.3}$Fe$_2$As$_2$, but with dramatically enhanced magnetic
scattering and elimination of superconductivity. This is different from the
suppression of the overall magnetic excitations in hole doped BaFe$_2$As$_2$
and the enhancement of superconductivity near optimal hole doping. These
results are consistent with density function theory plus dynamic mean field
theory calculations, suggesting that vanadium-doping in LiFeAs may induce an
enlarged effective magnetic moment $S_{eff}$ with a spin crossover ground state
arising from the inter-orbital scattering of itinerant electrons.
