Small metal-containing molecules have been detected and recognized as one of
the hybrid species efficiently formed in space; especially in the circumstellar
envelopes of evolved stars. It has been predicted also that more complex hybrid
species like those formed by metals and fullerenes (metallofullerenes) could be
present in such circumstellar environments. Recently, quantum-chemical
simulations of metallofullerenes have shown that they are potential emitters
contributing to the observed mid-IR spectra in the fullerene-rich circumstellar
environments of different types of evolved stars. Here we present the
individual simulated mid-IR (~5-50 um) spectra of twenty-eight metallofullerene
species; both neutral and charged endo- and exohedral metallofullerenes for
seven different metals (Li, Na, K, Ca, Mg, Ti, and Fe) have been considered.
The changes induced by the metal-C60 interaction on the intensity and position
of the spectral features are highlighted using charge density difference maps
and electron density partitioning. Our calculations identify the fundamental IR
spectral regions where, depending on the metal binding nature, there should be
a major spectral contribution from each of the metallofullerenes. The
metallofullerenes IR spectra are made publicly available to the astronomical
community, especially James Webb Space Telescope users, for comparisons that
could eventually lead to the detection of these species in space.Comment: Accepted for publication in The Astrophysical Journal Supplement
Series on 19 September 2023 (in press) (13 pages, 7 figures, and 1 table