Evidence for the stabilization of rectangular O+4 in solid neon

The reassignment of the 1320 and 2949 cm−1 absorptions of O+4, previously attributed to the trans isomer, is considered. A satisfactory least-squares force constant fit of the isotopic data for these two absorptions, assuming a rectangular structure, has been obtained. In accord with the results of ab initio calculations by Lindh and Barnes, it is concluded that, as previously proposed, the 1164 and 2808 cm−1 absorptions should be assigned to the trans ground state of O4+O, but that the rectangular isomer, which they calculated to lie at only slightly higher energy, may contribute the 1320 and 2949 cm−1 absorptions.