Photoelectron angular distributions from autoionizing 4s{sup 1}4p{sup 6}6p{sup 1} states in atomic krypton probed with femtosecond time resolution

Journal Article · Mon Mar 07 04:00:00 EST 2011 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.3547459· OSTI ID:21560043

Doughty, Benjamin; Haber, Louis H; Hackett, Christina; Leone, Stephen R ^[1]

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1. Departments of Chemistry and Physics and Lawrence Berkeley National Laboratory, University of California, Berkeley, California 94720 (United States)

Photoelectron angular distributions (PADs) are obtained for a pair of 4s{sup 1}4p{sup 6}6p{sup 1} (a singlet and a triplet) autoionizing states in atomic krypton. A high-order harmonic pulse is used to excite the pair of states and a time-delayed 801 nm ionization pulse probes the PADs to the final 4s{sup 1}4p{sup 6} continuum with femtosecond time resolution. The ejected electrons are detected with velocity map imaging to retrieve the time-resolved photoelectron spectrum and PADs. The PAD for the triplet state is inherently separable by virtue of its longer autoionization lifetime. Measuring the total signal over time allows for the PADs to be extracted for both the singlet state and the triplet state. Anisotropy parameters for the triplet state are measured to be {beta}{sub 2}= 0.55 {+-} 0.17 and {beta}{sub 4}=-0.01 {+-} 0.10, while the singlet state yields {beta}{sub 2}= 2.19 {+-} 0.18 and {beta}{sub 4}= 1.84 {+-} 0.14. For the singlet state, the ratio of radial transition dipole matrix elements, X, of outgoing S to D partial waves and total phase shift difference between these waves, {Delta}, are determined to be X= 0.56 {+-} 0.08 and {Delta}= 2.19 {+-} 0.11 rad. The continuum quantum defect difference between the S and D electron partial waves is determined to be -0.15 {+-} 0.03 for the singlet state. Based on previous analyses, the triplet state is expected to have anisotropy parameters independent of electron kinetic energy and equal to {beta}{sub 2}= 5/7 and {beta}{sub 4}=-12/7. Deviations from the predicted values are thought to be a result of state mixing by spin-orbit and configuration interactions in the intermediate and final states; theoretical calculations are required to quantify these effects.

• OSTI ID: 21560043
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 9 Vol. 134; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ANGULAR DISTRIBUTION
ANISOTROPY
ATOM COLLISIONS
AUTOIONIZATION
COLLISIONS
CONFIGURATION INTERACTION
COUPLING
DEFECTS
DIPOLES
DISTRIBUTION
ELECTRON SPECTROSCOPY
ELECTRONS
ELEMENTARY PARTICLES
ELEMENTS
ENERGY
FERMIONS
FLUIDS
GASES
INTERMEDIATE COUPLING
IONIZATION
KINETIC ENERGY
KRYPTON
L-S COUPLING
LEPTONS
MATRIX ELEMENTS
MULTIPLETS
MULTIPOLES
NONMETALS
PARTIAL WAVES
PHASE SHIFT
PHOTOELECTRON SPECTROSCOPY
PHOTON COLLISIONS
PHOTON-ATOM COLLISIONS
PULSES
RADIATION DOSE UNITS
RARE GASES
RESOLUTION
SIGNALS
SPECTROSCOPY
TIME RESOLUTION
TIMING PROPERTIES
TRIPLETS
UNITS