| The photoionization dynamics of the nitric oxide (NO) molecule is studied by angle- and energy-resolved photoelectron spectroscopy coupled with two-color resonance enhanced multiphoton ionization (REMPI). Optically aligned NO molecules in a specific vibration-rotation level of the NO {dollar}A sp2Sigmasp+{dollar} or {dollar}D sp2Sigmasp+{dollar} state are prepared by one-photon excitation of ground-state NO, and are subsequently excited either to the direct ionization continuum of NO that yields the NO{dollar}sp+ X sp1Sigmasp+ (vsp+ = 0){dollar} ion or to a single rovibronic level of a high-lying nl Rydberg state {dollar}(11 ge n le 15; 0 le lsb{lcub}R{rcub} le 3){dollar} that undergoes vibrational autoionization to form the same ion. The energy of the photoelectron is measured by time of flight with sufficient resolution that photoelectron peaks associated with the individual rotational levels {dollar}Nsp+{dollar} of the NO{dollar}sp+{dollar} ion are resolved. The photoelectron angular distributions (PADs) are measured by varying the linear polarization directions of one or both laser beams with respect to the flight axis. By analyzing these quantum-state-specific PADs based on a newly developed theoretical formalism, we uniquely determined the dynamical parameters that describe not only the direct photoionization dynamics of the individual ionizing state but also the scattering dynamics between the photoelectron and the NO{dollar}sp+ X sp1Sigmasp+ (vsp+ = 0){dollar} ion. The resulting dynamical parameters also provide a detailed quantitative insight into the Cooper minimum in the photoionization of the NO D state. The rotationally resolved photoelectron spectra obtained from vibrational autoionization of individual quantum levels of nl Rydberg states show that many rotational levels of the NO{dollar}sp+{dollar} ion are populated after the autoionization events and provide the first experimental evidence for extensive angular momentum exchange between the outgoing electron and the NO{dollar}sp+{dollar} ion core caused by the vibrational-quantum change of the core. |
