Optical absorption spectrum of the silver dimer ion: Temperature dependence measured by photodissociation and photon-trap spectroscopy

The optical absorption spectrum is reported for the silver dimer cation, Ag₂ ⁺, which is temperature-controlled by buffer-gas cooling in an ion trap. The measurement is performed by two methods, photodissociation and photon-trap spectroscopy. The temperature of the trapped ions is estimated from the profiles of the spectrum. The spectrum is further analyzed to evaluate the bond length, r _e, the vibrational frequency, ω _e, and the anharmonic constant, ω _e x _e, in the first excited electronic state based on the molecular parameters reported for the ground state. Absorption and dissociation cross sections are compared as well.