Two-photon resonant three-photon ionization of the nd /sup 2/D states of cesium, rubidium, and sodium: Photoelectron angular distributions

Journal Article · Wed Apr 01 04:00:00 EST 1987 · Phys. Rev. A; (United States)

DOI:https://doi.org/10.1103/PhysRevA.35.2878· OSTI ID:5948843

Dodhy, A; Stockdale, J A.D.; Compton, R N; Tang, X; Lambropoulos, P; Lyras, A

Energy-resolved photoelectron angular distributions have been measured for the nd /sup 2/D states (n = 11--23) in cesium and rubidium atoms for two-photon resonant, three-photon ionization under conditions where the spin-orbit fine structure was not resolved. The photoelectron angular distributions reveal strong fine-structure mixing effects when the time duration of the laser pulse is longer than the time corresponding to the inverse of the fine-structure splitting of the nd states involved. Three-photon ionization photoelectron angular distributions for sodium atoms have been studied both experimentally and theoretically for laser frequencies in which resonance enhancement occurs via the two-photon excited nd /sup 2/D states (n = 5--9). The laser pulse duration is approx.6 ns which is comparable to or less than the fine-structure mixing time for the unperturbed fine-structure nd /sup 2/D/sub 5/2,3/2/ levels. In addition, the high laser powers approx. 10/sup 8/ W/cm/sup 2/ employed result in alterations of the energy separations of the fine-structure levels (and cause corresponding changes in the mixing times) due to the ac Stark effect. A detailed theoretical analysis is presented and good agreement is obtained with the experimental results.

• Research Organization: Chemical Physics Section, Health and Safety Research Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831
• OSTI ID: 5948843
• Journal Information: Phys. Rev. A; (United States), Journal Name: Phys. Rev. A; (United States) Vol. 35:7; ISSN PLRAA
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ALKALI METALS
ANGULAR DISTRIBUTION
CESIUM
CONFIGURATION MIXING
DISTRIBUTION
ELECTROMAGNETIC RADIATION
ELECTRON EMISSION
ELEMENTS
EMISSION
ENERGY RESOLUTION
FINE STRUCTURE
INTERACTIONS
IONIZATION
LASER RADIATION
METALS
MULTI-PHOTON PROCESSES
PHOTOIONIZATION
PULSES
RADIATIONS
RESOLUTION
RUBIDIUM
SODIUM