  We present a method for computing angle-resolved electron-energy-loss and
gain spectroscopies for phonon and magnon excitations in transmission electron
microscopy. Fractional scattering intensities are derived from the
temperature-dependent time auto-correlation of the electron beam wave function.
This method captures both single and multiple scattering processes, as well as
dynamical diffraction effects. Our method remains computationally efficient,
and it is easy to parallelize.
