RESONANTLY ENHANCED MULTIPHOTON-IONIZATION PHOTOELECTRON-SPECTROSCOPY OF KRYPTON AND XENON - EXPERIMENT AND THEORY

Angular distributions for energy-resolved photoemitted electrons from resonantly enhanced multiphoton ionization (REMPI) via the two-photon allowed 6p[j = 1/2]J = 0, 6p[3/2]2, 6p'[1/2]0, 6p'[3/2]2, 7p[1/2]0, 7p[3/2]2, and 7p[5/2]2 states and the three-photon allowed 7s[3/2]1, 8s[3/2]1, 9s[3/2]1, 5d[3/2]1, 5d'[5/2]3, and 5d'[3/2]1 states of xenon and the three-photon allowed 5s[3/2]1, 6s[3/2]1, 4d[3/2]1, 4d[5/2]3, and 4d[7/2]3 states of krypton are reported. In one case, two-photon resonant, three photon ionization [(2 + 1) REMPI] of the 6p'[1/2]0 state of xenon, a dramatic laser-power dependence (power approximately 1.5 x 10(10) to approximately 3 x 10(10) W/cm2), was observed. The measured angular distributions for electron leaving either ion core (2P1/2 or 2P3/2) are compared with those calculated from multichannel quantum-defect theory. Reasonable agreement is obtained in reproducing the general features of the angular distributions for the p and d states in the rare gases. However, discrepancies are observed for some of the s states. Comparison of the measured and calculated branching ratios for leaving either ion core also shows good agreement for the p and d states, but shows that there are inadequacies in the theory for describing the s states. We also report the photoelectron energy and angular distributions for the (4 + 1) REMPI process via the 6p[1/2]0 and 6p[3/2]2 states of xenon. Photoelectrons due to above-threshold ionization, (4 + 2), resonantly enhanced via the four-photon allowed 6p[1/2]0 state, are also observed.