Complete description of linear molecule photoionization achieved by vector correlations using the light of a single circular polarization

Abstract

In this paper we demonstrate that the vector correlation approach for the study of dissociative photoionization (DPI) of linear molecules enables us to achieve a complete description of molecular photoionization by performing a single experiment using only one state of circularly, or elliptically, polarized light. This is illustrated by the derivation of the complex dipole matrix elements for the benchmark DPI reaction of the NO molecule, where (4σ)−1 inner-valence ionization is induced by left-handed circularly polarized synchrotron radiation at hν=23.65 eV. The importance of electronic correlation for this process is emphasized by comparing the experimental results with multichannel Schwinger configuration interaction calculations. The energy dependence of the transition matrix elements and that of the electronic correlation in the 25–40 eV energy range are illustrated by the calculations and compared with the present results and recent experimental studies at 40.8 eV.

Circular dichroism in molecular-frame photoelectron angular distributions in the dissociative photoionization ofH2andD2molecules

“…For instance, the multichannel Schwinger configuration-interaction method (MC-SCI) of Lucchese and co-workers [33][34][35] has been shown to provide accurate predictions of molecular-frame photoemission observables measured for a series of molecular targets [20][21][22]30,31]. Density functional theory (DFT) calculations have also been conducted and predict richly structured measured angular distributions from fixed-in-space small polyatomic molecules [36], with recent developments involving time-dependent DFT [37].…”

“…To emphasize the geometrical aspect of these functions, the latter dependence has been omitted in the notation. When photoionization is fast in comparison with dissociation of the molecular ion [20], variations with total energy are entirely due to variations in the photoelectron energy, since the nuclei barely move and therefore their kinetic energy remains nearly constant [20]. However, when, as in the present study, both ionization and dissociation occur on a comparable time scale, the energy in the final state is shared between electrons and nuclei, and consequently the F LN (θ e ) functions do vary with the photoion kinetic energy [28,32].…”

“…1 takes a remarkably simple general form in the dipole approximation for incident circularly polarized light [20,30] [here μ 0 = 0 is for linearly polarized light and, for instance, μ 0 = +1 indicates lefthanded circularly (LHC) polarized light of positive helicity h = +1]:…”

“…This kind of complete experiments has been extended nowadays to photoionization of molecules in the ground state, taking advantage of dissociative ionization and using multicoincidence detection methods like those mentioned above. By using these methods, CDAD has been observed [17][18][19][20][21][22][23][24][25] in molecular-frame photoelectron angular distributions (MFPADs) of oriented achiral molecules such as N 2 , CO, NO, O 2 , N 2 O, H 2 , and D 2 , following direct or resonant inner-and valence-shell photoionization.…”

“…104, 233003 (2010)]. In this work we present a detailed study of circular dichroism in the photoelectron angular distributions of H 2 and D 2 molecules, oriented perpendicularly to the propagation vector of the circularly polarized light, at different photon energies (20,27, and 32.5 eV). Circular dichroism in the angular distributions at 20 and to a large extent 27 eV exhibits the usual pattern in which inversion symmetry is preserved.…”