Photoemission in the NO molecular frame induced by soft-x-ray elliptically polarized light above theN(1s)−1andO(1s)−1ionization thresholds

Abstract

Complete experiments in inner-shell photoionization of linear molecules are achieved by combining the velocity vector correlation method, based on imaging and time-of-flight-resolved electron-ion-ion coincidence technique, with the use of elliptically polarized light. We report here on the molecular frame photoelectron angular distributions (MFPADs) obtained using this method in a single experiment performed with elliptically polarized light, for a site selective $K$-shell ionization of the NO molecule in the region of the $\mathrm{N}{(1s)}^{\ensuremath{-}1}$ and $\mathrm{O}{(1s)}^{\ensuremath{-}1}$ shape resonances. For a comparable photoelectron energy the $\mathrm{N}{(1s)}^{\ensuremath{-}1}$ and $\mathrm{O}{(1s)}^{\ensuremath{-}1}$ MFPADs display a remarkable symmetry in the inversion with respect to the emission center of the NO molecule, while revealing common features such as, in particular, the dominant role of $p$ and $f$ partial-wave channels in the photoelectron emission. A large molecular frame circular dichroism is observed. These results are well predicted by multichannel Schwinger configuration interaction calculations (MCSCI), which provide additional information for $\mathrm{N}{\mathrm{O}}^{+}(^{3}\ensuremath{\Pi})$ and $\mathrm{N}{\mathrm{O}}^{+}(^{1}\ensuremath{\Pi})$ multiplet specific photoionization reactions. The analysis of the photoelectron-ion-ion kinetic energy correlation characterizes the ionic fragmentation channels populated after Auger decay of the $\mathrm{N}{\mathrm{O}}^{+}{(1{s}_{\mathrm{N}∕\mathrm{O}})}^{\ensuremath{-}1}$ ionic states.