Anionic hydrogen clusters as a source of diffuse interstellar bands
  (DIBs)
  The sources behind numerous key diffuse interstellar bands (DIBs) remain
elusive, and thus evidence is presented here that a family of seven anionic
hydrogen atomic clusters (H(-)2n+1, n = 1 to 7) are pertinent contributors.
Configuration interaction calculations show hat these charge-induced dipole
clusters are stable at temperatures characteristic of the interstellar medium,
and emerge from the most abundant element in the Universe. The clusters'
spectra yield 25 absorption optical lines that align with observed DIBs to
within the computational uncertainties. The absorption bands are due to
excitations from the ground states of the clusters to metastable states.
