| Autor: |
P O'Keeffe, A Mihelič, P Bolognesi, M Žitnik, A Moise, R Richter, L Avaldi |
| Jazyk: |
angličtina |
| Rok vydání: |
2013 |
| Předmět: |
|
| Zdroj: |
New Journal of Physics, Vol 15, Iss 1, p 013023 (2013) |
| Druh dokumentu: |
article |
| ISSN: |
1367-2630 |
| DOI: |
10.1088/1367-2630/15/1/013023 |
| Popis: |
Two-photon resonant photoionization of helium is investigated both experimentally and theoretically. Ground state helium atoms are excited to the 1s4p, 1s5p and 1s6p ^1 P states by synchrotron radiation and ionized by a synchronized infrared pulsed picosecond laser. The photoelectron angular distributions of the emitted electrons are measured using a velocity map imaging (VMI) spectrometer. The measured asymmetry parameters of the angular distribution allow the phase differences and the ratios of the dipole matrix elements of the 1s ϵ s and 1s ϵ d channels to be determined. The experimental results agree with the calculated values obtained in a configuration–interaction calculation with a Coulomb–Sturmian basis set. The effects of the radiative decay of the intermediate state and the static electric field of the VMI spectrometer on the measurements are discussed. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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