Dissociation Dynamics of CO2 on Cu(110) Studied Over a Wide Range of Incident Energies

In this work, we have studied the dissociation dynamics of CO2 on a Cu(110) surface using molecular beams with incidence energies ranging from 0.28 eV to 4.6 eV. The incident energy dependence of the initial dissociative reaction probabilities (S0) of CO2 showed two distinct characteristics. At first, S0 exhibits a rapid increase from 1.8 × 10−4 at 0.28 eV to more than 150-fold at 2 eV. Beyond this, only a small increase by less than a factor of 1.5 was observed in the 2 eV to 4.6 eV range, with the S0 being 4.1 × 10−2 at 4.6 eV. Incident angle-dependent measurements reveal total energy scaling to be followed. Measurements using a heated nozzle showed no observable enhancement in S0 due to the vibrational energy of the incident molecules, with an upper limit of vibrational efficacy estimated to be 0.25. Furthermore, an increase in O-atom saturation coverage (resulting from CO2 dissociation) from 0.5 ML to 0.66 ML was observed at high impact energies (> 3 eV), suggesting that newer dissociation sites become accessible at higher energies.