Photoelectron angular distributions from polarized Ne*atoms near threshold

Near-threshold photoelectron angular distributions from two-photon resonant photoionization of He

“…Furthermore, since the number of accessible channels is small, the number of independent parameters in (7) and (8) is also small. This is in contrast with a two-photon two-colour photoionization of neon atoms proceeding through the 2p 5 3d states [22], where a larger number of parameters were necessary for the description of the PADs and where it was shown that a simplified treatment neglecting the coupling details of various channel functions resulted in incorrect values of the asymmetry parameters.…”

“…where cos θ =k ·ê 1 =k ·ê 2 , σ (2) int is the integrated generalized two-photon cross-section and P q is the Legendre polynomial of order q. The asymmetry parameters can be expressed with the coefficients A q as β 2 = A 2 /A 0 and β 4 = A 4 /A 0 [22].…”

Effect of electronic angular momentum exchange on photoelectron anisotropy following the two-color ionization of krypton atoms

“…This is challenging because the relatively low photon flux of the SR is not well suited to resonant multiphoton schemes, but the technique has been demonstrated in a few cases. [16][17][18] In a recent study of direct relevance to the one reported here, Meyer and coworkers have reported polarization-dependent PADs following the resonant photoionization of Xe atoms which were state-selected by SR and ionized by visible laser radiation. 19,20 In their work, ionization was enhanced through the use of an autoionizing resonance, and only a single ionic state was energetically accessible.…”

Electron angular distributions of noble gases in sequential two-photon double ionization

“…Whereas in single-photon ionization the photoemission angular distribution is characterized by a single anisotropy parameter, higher order contributions with according parameters have to be added in the description of multi-photon ionization. Anisotropy patterns of that kind are known from studies of polarized targets which were prepared and ionized by two different light sources (HHG and synchrotron radiation) [21][22][23]. In those experiments, the values of the anisotropy parameters β 2 and β 4 of the two-step process and differences for partial waves of different angular momentum have been determined.…”