Quantifying Relativistic Interactions from Angular Momentum Partitioning Measurements during Photoionization

Abstract

We have measured the degree of helicity of fluorescent radiation from Ar+[3p4[3P]4p] 2P(o)1/2 formed by circularly polarized synchrotron radiation in the region of double excitations converging to Ar+3p4 nl satellite states. Angular momentum coupling allows the partitioning of the one unit of angular momentum brought into the system to be demarcated. We obtain a nonvanishing expectation value of the total spin of the residual ion-photoelectron system indicating significant relativistic interactions during the photoionization process.

Alignment following Au L3photoionization by synchrotron radiation

“…In photoionization the alignment was first observed in Cd by Caldwell and Zare [4]. Recent photoionization experiments have used synchrotron radiation for measurements of the alignment [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. Most of the experimental results were basically in agreement with the theoretical calculations [20][21][22][23].…”

Effect of Relativistic Many-Electron Interactions on Photoelectron Partial Wave Probabilities

“…These interactions manifest themselves through the production of quartet states in the residual excited ion of closed shell atoms [7 -9], spin polarization of emitted electrons [10,11], and as we have shown in an earlier Letter [12], through the orientation of the 2 P o 1͞2 state of the residual Ar 1 . In these processes, a complete determination of the partial wave probabilities of the photoelectron is especially important for a detailed understanding of relativistic dynamics.…”

Use of partial-wave decomposition to identify resonant interference effects in the photoionization–excitation of argon

“…The relative fluorescence intensity for all six excited states of Ar II are shown in figure 4, in conjunction with the theoretical results. Experimental results for both the 2 P states have been published previously [9][10][11][12]. Theoretical cross sections for the 4 states have also been published previously [24].…”

“…As third generation synchrotrons have come on line, the possibility of making such measurements in this energy range with resolution of a few meV-comparable to absorption measurements [1,2]-has been realized. More recently, polarization analysis of the fluorescence has been shown to have the ability to yield even finer detail about the final state of the photoionization reaction by identifying outgoing electron partial waves and/or the alignment and orientation of the residual ion [8][9][10][11][12].…”