  The interpretation of the more than 300 diffuse interstellar bands (DIBs) is
one of the most long-standing problems in interstellar spectra since the two
first bands were reported in 1921. We now predict the frequencies of 260
diffuse interstellar bands (DIBs) using the Rydberg Matter model we have
developed previously. These transitions involve mainly He atoms, but other
two-electron atoms like Ca and other metals can take part in the absorption
processes. Approximately 70% of the total intensity of the DIBs is due to
absorption in doubly excited states and 30% in singly excited He atoms. The
doubly excited states are in inverted states while the He atoms are thermal.
The possibilities to observe DIBs in the UV and NIR ranges are discussed and
band positions are predicted.
