The structures of Inn±1 clusters are same from the Inn clusters.
The stability analysis shows Inn− clusters are much higher than that of neutral Inn and cationic Inn+ clusters.
In15 has the smallest AIP value and In4 has the smallest VIP value.
The oscillation tendency of HOMO–LUMO energy gaps are the inverse for Inn+ and Inn clusters with Inn− clusters.
In8 cluster is found that the charges are equal for each In atom.