\[V\left(a,z\right)=\frac{e^{-\frac{1}{4}z^{2}}}{2\pi}\*\left(\int_{-ic-\infty}^%
{-ic+\infty}+\int_{ic-\infty}^{ic+\infty}\right)e^{zt-\frac{1}{2}t^{2}}t^{a-%
\frac{1}{2}}\,\mathrm{d}t,\]