Radiative cooling of cationic carbon clusters, CN+, N = 8, 10, 13–16

The radiative cooling of highly excited carbon cluster cations of sizes N = 8, 10, 13–16 has been studied in an electrostatic storage ring. The cooling rate constants vary with cluster size from a maximum at N = 8 of 2.6 × 104 s−1 and a minimum at N = 13 of 4.4 × 103 s−1. The high rates indicate that photon emission takes place from electronically excited ions, providing a strong stabilizing cooling of the molecules.