In the shown AC circuit phase difference between currents I₁ and I₂ is 

In the upper branch containing C, current ${\mathrm{I}}_1$ leads supply voltage by $\frac{\mathrm{\pi }}{2}$.

In the lower branch containing L and R, current ${\mathrm{I}}_2$ lags supply voltage by $\mathrm{\varphi }={\tan }^{-1}\frac{{\mathrm{X}}_{\mathrm{L}}}{\mathrm{R}}$.

Hence the total phase difference between the ${\mathrm{I}}_1$ and ${\mathrm{I}}_2$ is $\frac{\mathrm{\pi }}{2}+{\tan }^{-1}\frac{{\mathrm{X}}_{\mathrm{L}}}{\mathrm{R}}$.