Dynamic structure factor is the spatial and temporal Fourier transform of Van Hoves time dependent pair correlation function. It is written as
$$ S(k,\omega)= \frac{1}{2\pi}\int F(k,t)\exp(i\omega t)dt $$
$F(k,t)$ is intermediate scattering function. My question is how did we use spatial and temporal Fourier Transform of Van Hoves to get dynamic structure factor? and what does spatial and temporal Fourier transform mean?