Effects of electron correlations on photoionization and multiphoton ionization

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1989

OSTI ID:5931331

Wijesundera, W P

Photoionization processes in atoms are investigated with particular attention paid to the effects of electron correlations. Studies of electron correlations have been carried out in three different atoms: yttrium, argon and barium. Many-Body Perturbation Theory (MBPT) was used to calculate the photoionization cross section of the neutral yttrium atom from threshold at 6.52 eV to 100.00 eV. The resonance structure due to 4p excitations to 4d states was also calculated. The effects of electron correlations were found to be quite significant at low energies. MBPT was also used to calculate photoionization cross sections with excitation of the neutral argon atom from the single ionization threshold at 15.76 eV to 100.00 eV. Resonance structure due to both single electron excitations (3s {yields} np) and double electron excitations (3s{sup 2}3p{sup 6} {yields} 3s{sup 2}3p{sup 4}nm) was included. Calculated cross sections, leaving the ion in 3s{sup 2}3p{sup 5}, 3s3p{sup 6}, 3s{sup 2}3p{sup 4}({sup 1}D)md({sup 2}S) and 3s{sup 2}3p{sup 4}4p({sup 2}P) levels, the total cross section, and the angular asymmetry parameter for the 3p partial cross sections are compared with experiment and previous calculations. The two photon ionization cross section for the neutral barium atom was also investigated. A double perturbation expansion in the Coulomb correlations and the atom-radiation field interaction was made, and the differential equation method was used for carrying out an infinite summation implicitly over the intermediate states. The effects of electron correlations were investigated.

• Research Organization: Virginia Univ., Charlottesville, VA (USA)
• OSTI ID: 5931331
• Country of Publication: United States
• Language: English

Related Subjects

640302* -- Atomic
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ALKALINE EARTH METALS
ARGON
ATOMS
BARIUM
COMPARATIVE EVALUATIONS
CORRELATIONS
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY RANGE
ENERGY-LEVEL TRANSITIONS
EV RANGE
EV RANGE 01-10
EV RANGE 10-100
EXCITATION
FERMIONS
FLUIDS
GASES
IONIZATION
LEPTONS
MANY-BODY PROBLEM
METALS
MULTI-PHOTON PROCESSES
NONMETALS
PERTURBATION THEORY
PHOTOIONIZATION
RARE GASES
TRANSITION ELEMENTS
YTTRIUM