Long lived (0.8 ms, 6 ms, and >3.8 s) states in ${\mathrm{CO}}^{2+}$ have been observed for the first time by monitoring beams of 75–300 keV ions in the ion storage ring ASTRID. It is the first experimental evidence that a doubly charged molecule can be stable on a time scale of seconds. The results are theoretically interpreted by means of a multichannel Schrödinger analysis based on ab initio computations of potential energy curves and off-diagonal spin-orbit couplings. This analysis indicates that ${}_{}{}^3{}_{}{}^{}\mathrm{\Pi }$(ν=0) accounts for the long lived component. The two decay components in the ms range probably derive from higher excited states in ${\mathrm{CO}}^{2+}$.

• Received 11 May 1993

DOI:https://doi.org/10.1103/PhysRevLett.71.1812