Photoionization matrix elements

Experimental results from well-resolved spectra With known wavefunctions F, for the final ionic states of the 2Se manifold one can calculate the photoionization matrix elements for all processes leading to a selected F,. Using for simplicity an uncorrelated wavefunction of the initial state... 

Photon-atom interaction and photoionization matrix elements... 

The dynamical parameters 11(1, k2, k3) are fixed by the photoionization matrix elements, e.g., in the LSJ-coupling approximation by the radial dipole integrals es,2P and Pcd 2p and the relative phase A, as follows ... 

The photoionization matrix elements, Cnc,kix(R, ), in Eq. (3.59) is explicitly dependent on the nuclear geometry and photoelectron momentmn, and is the essential ingredient in describing the molecular photoionization dynamics. It is built from geometry-dependent partial-wave dipole matrix elements between the neutral and ionized states, Inc,kiXfi(R),... 

Fig. 3.5 Potential curves for the X and (2) states of Na2 and the X state of NaJ. The transition dipole moment function fj,ge and photoionization matrix elements Qm for the molecule parallel to the pump and probe polarization are also shown for a kinetic energy of 0.60 eV. The partial waves I = 0, 2, and 4 with m = 0 are denoted by long, medium, and short dashed lines, respectively. (Reprinted with permission from Y. Arasaki et al, J. Chem. Phys. 112, 8871 (2000)).

We have used the formulation, potential curves (see Fig. 3.5), and photoionization matrix elements outlined in the previous sections to study the pump-probe photoelectron spectra in Na2. Important parameters in these studies include. 

The photoionization matrix elements employed in these studies are obtained using high-quality wavefunctions for the bound states and photoelectron continuum. Preliminary results for this calculation were presented earlier... 

In this section we extend these earlier studies by employing robust values of the photoionization matrix elements in calculations of the time-resolved photoelectron spectra for ionization into the singlet and triplet ion states. We also report the photoelectron angular distributions for these... 

The photoelectron angular distributions from the B state of LiH (H-state) and all the others considered (X, A, C states having S symmetry) are qualitatively different from each other. Therefore future incorporation of geometry- and orientation-dependent photoionization matrix elements should enhance the understanding of information that may be obtained from such a study of the electron and nuclear dynamics. 

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