Effects of Cooper minima in resonance enhanced multiphoton ionization‐ photoelectron spectroscopy of NO via the D 2Σ+ and C 2Π Rydberg states

Rotationally resolved photoelectron spectra in resonance enhanced multiphoton ionization of H2O via the C 1 B 1 Rydberg state Photoelectron studies of resonantly enhanced multiphoton ionization of H2 via the B' 1Σ+ u and D 1Π u states J. Cooper minima are predicted to occur in the 3pu-+ku(/ = 2) and 3pu-+k1T(/ = 2) channels in the resonance enhanced multi photon ionization of NO via the D 2~ + (3pu) Rydberg state. The low energy ku(1= 2) Cooper minimum leads to the observed t:.N = N +-N' = 0 photoelectron peak, in addition to the t:.N = ± 1, ± 3 peaks seen in the rotational spectra. The Cooper minima are accompanied by significant I mixing in the continuum due to the nonspherical molecular potential and result in a strong dependence of rotational branching ratios and angular distributions on photoelectron kinetic energy. A Cooper minimum is also predicted in the 3P1T-.ko(/ = 2) channel for photoionization of the C 2IT(3p1T) Rydberg state. The effect of this Cooper minimum on photoelectron spectra and photoelectron angular distributions is also investigated.