- and Energy-Resolved Photoelectron Spectroscopy: a Probe of Photoionization Dynamics.
Abstract
The dynamics of photoionization are explored through a two-color high-resolution angle- and energy-resolved study of the photoelectrons produced in the (1 + 1 ^') resonance enhanced multiphoton ionization of NO via the A^2Sigma ^+ (nu = 0) state. We find markedly different photo-electron angular distributions arising from production of ions in different rotational states (DeltaN = 0, +/- 1, +/-2 transitions in the ionization step). We also observe that the Delta N = +/-2 angular distributions are very sensitive to the intermediate state alignment. A general model is put forward in which experimental observables (angle- and energy-resolved photoelectron spectra) are used to determine the attributes (relative amplitudes and phase shifts) of a small number of interfering continuum channels that contribute to the ionization step as well as the fraction of parallel character of the ionization step. Nearly 70% of the ejected photoelectrons are associated with the DeltaN = 0 ionization transition; the partial wave composition of these electrons is dominated by p-character. The less important Delta N = +/-1 peaks have both s - and d-wave character. The DeltaN = +/-2 photoelectron peaks exhibit far more f-wave than p-wave character because destructive interference removes nearly all of the p-wave contribution to the angular distribution. The partial wave decomposition is used to predict angular distributions resulting from excitation of the intermediate state by different rotational branch transitions; these predictions are in excellent agreement with the measured distributions.
- Publication:
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Ph.D. Thesis
- Pub Date:
- 1989
- Bibcode:
- 1989PhDT........49A
- Keywords:
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- Chemistry: Physical; Physics: Molecular