  A G{\"o}rling-Levy (GL)-based perturbation theory along the range-separated
adiabatic connection is assessed for the calculation of electronic excitation
energies. In comparison with the Rayleigh-Schr{\"o}dinger (RS)-based
perturbation theory introduced in a previous work [E. Rebolini, J. Toulouse, A.
M. Teale, T. Helgaker, A. Savin, Mol. Phys. 113, 1740 (2015)], this GL-based
perturbation theory keeps the ground-state density constant at each order and
thus gives the correct ionization energy at each order. Excitation energies up
to first order in the perturbation have been calculated numerically for the
helium and beryllium atoms and the hydrogen molecule without introducing any
density-functional approximations. In comparison with the RS-based perturbation
theory, the present GL-based perturbation theory gives much more accurate
excitation energies for Rydberg states but similar excitation energies for
valence states.
