Recombination of 5-eV O(3p) Atoms with Surface-Adsorbed NO: Spectra and TheirDependence on Surface Material and Temperature

摘要

Recombination spectra are measured in the wavelength range 300-850 nm resultingfrom collisions of 5-eV O(3p) atoms with NO adsorbed on MgF2, Ni, and Ti surfaces. The dependence of the chemiluminescence intensity on surface temperature (240-340 K) is measured, and activation energies for desorption of the physisorbed NO obtained. Activation energies as a function of wavelength for each material are also reported. It is found that, with minor variations, the recombination spectra are similar for the three surfaces, and that the emitter is very likely electronically excited NO2. All three materials exhibit a greater tendency to emit at the lower temperatures. MgF2 has the greatest tendency to chemiluminesce, followed by Ni then Ti. Also, the activation energies for NO desorption are similar for the surfaces, and are independent of emission wavelength. The results are interpreted as a single mechanism of removal, with increasing T, of physisorbed NO from saturated surfaces of different coverage.