Complete photoionization experiment in the region of the 2 _{g   u}shape resonance of the N₂molecule

Abstract

Angular distributions of photoelectrons (ADPs) from the 2σg shell of a fixed-in-space N2 molecule have been measured for left- and right-elliptically polarized, as well as for linearly polarized, light. From these data a set of dipole matrix elements and phase shift differences characterizing the process has been determined taking into account the acceptance angles of both electron and ion detectors, i.e. the complete experiment has been performed. Good agreement between the experimental and the relevant theoretical values calculated in the random phase approximation is obtained. Based on the results of the complete experiment, three-dimensional ADPs and ions are predicted for different light polarizations.

Structure determination of molecules in an alignment laser field by femtosecond photoelectron diffraction using an X-ray free-electron laser

“…Figure 2(b) shows the polar plot of the angular distribution of the I 2 p photoelectrons (detailed in the Methods section), which is hereafter referred to as the XPD profile. The XPD profiles of reflection-symmetric molecules, like the I 2 molecule, that are aligned parallel to the polarization vector of the XFEL pulse, can be expressed by a series of even-order Legendre polynomials P n ( θ e ) (refs 18, 19, 20), where θ e is the photoelectron ejection direction with respect to the molecular axis. In fact, the measured XPD profile is well reproduced by the Legendre polynomials of up to the 6th orders (see Fig.…”

“…XPD profiles are affected by the geometry of the polarization vector of the X-rays and the molecular axis181920. Therefore, the observed XPD profile of the laser-aligned molecules is the weighted sum of the XPD profiles over the molecular axis distributions that are described by the degree of alignment.…”

CarbonK-shell photoionization of fixed-in-spaceC2H4<

“…Strictly speaking, however, the above fitting functional form (m = 0, ±1) works only for linear molecules like O 2 , N 2 (see [23]), or even C 2 H 2 . Another linear but not symmetric molecule that was a subject of a similar treatment in [24] is CO. On the other hand, C 2 H 4 is a planar molecule, not linear, which was taken fully into account by the theoretical model.…”

Circular Dichroism in Photoionization ofH2

“…In the gas phase, circular dichroism was first observed in the photoionization of NO molecules that were aligned by multiphoton absorption into a well-defined excited state [15]. Circular dichroism has also been observed [16][17][18][19][20] in molecular-frame photoelectron angular distributions (MFPADs) of randomly oriented achiral molecules (hereafter called ''circular dichroism in the angular distribution,'' CDAD). In this case, the three vectors can be unambiguously determined by detecting in coincidence photoions and photoelectrons that result from the one-photon dissociative ionization of the molecule.…”