About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Paper
The interaction of highly vibrationally excited molecules with surfaces: Vibrational relaxation and reaction of NO(v) at Cu(111) and O/Cu(111)
Abstract
We have studied the reaction and inelastic scattering of ground and vibrationally excited NO on Cu(111). We employed laser-based techniques to prepare NO in vibrationally excited states, stimulated emission pumping (SEP) to prepare v = 13 and v = 15 and infrared overtone pumping to prepare v = 2. Laser ionization detection schemes were developed for probing the state distribution of highly vibrationally excited NO molecules. Ground-state NO(v = 0) dissociates at Cu(111) with a probability of ≈2 × 10-4, with little dependence on the translational energy in the range between 29 and 65 kJ mol-1. The dissociation probability is strongly enhanced by vibrational excitation to v = 13 and 15. The dissociation continues until the oxygen coverage on Cu(111) reaches saturation. For highly excited NO(v = 13, 15) scattering from O/Cu(111), we have seen efficient multi-quantum relaxation (up to Δv = -5). For NO(v = 2), in contrast, the survival probability is nearly 90%. Measurements of the translational and rotational state distributions after scattering support a direct-inelastic mechanism for vibrational relaxation, with strong flow of energy into the surface. The branching ratios for vibrational relaxation are independent of the kinetic energy in our experiments.