Quantum-state distributions for the HD product of the direct reaction of H(D)/Cu(111) with D(H) incident from the gas phase

Abstract

We have determined the internal‐state distribution for the HD product of the reaction of gas‐phase D atoms with H atoms chemisorbed on Cu(111) and for the corresponding reaction of H atoms with chemisorbed D atoms. In the case of D‐on‐H, the populations of the vibrational states v=0, 1, 2, and 3 are comparable, while that for v=4 is considerably smaller, giving a mean vibrational energy of ∼0.7 eV. The vibrational state distribution for H‐on‐D is similar, but in this case there is a clear peak at v=1, even less population in v=4, and a somewhat smaller mean vibrational energy of ∼0.6 eV. The mean rotational energy falls with increasing v in both cases, ∼0.5 eV for v=0 to v=4, with an overall mean rotational energy of ∼0.4 eV. The rotational distributions are distinctly narrower for H‐on‐D than for D‐on‐H. The maximum internal energy observed is ∼2.3 eV, consistent with the total energy available to the product. Results are consistent with recent calculations.