What are the cross-sections for neutral-impact excitation?

One way for bound electrons in an atom (e.g. neutral helium) to transition to a higher energy level is via electron-impact excitation (i.e. collisions with free electrons). Accordingly, one can compute photon emission rates since the excited electron will eventually radiatively decay back to the ground state (e.g. 587.6 nm line in HeI). Such photon emission rates can be found in databases (e.g. OPEN-ADAS) as a function of the density and temperature of the free electrons colliding with the atom. But in such databases, excitation only due to collisions with free electrons appears to be present.

Analogous to electron-impact excitation, are neutral-impact excitations, i.e. neutral helium colliding with other neutral helium atoms, important for excitation? Do emission rates due to such neutral-neutral inelastic collisions exist anywhere perhaps as a function of the neutral atom’s density and temperature? To help get a better understanding, any quantitative comparisons of the cross-sections of electron-impact and neutral-impact excitations (and possibly even ion-impact for intuition, e.g. ionized helium nucleus colliding with neutral helium atoms) would be helpful.