Photoelectron angular distribution

Althorpe S C and Seideman T 1999 Molecular alignment from femtosecond time-resolved photoelectron angular distributions nonperturbative calculations on NO J. Chem. Phys. 110 147... 

Symmetry Properties of Legendre Polynomial Coefficients in the Photoelectron Angular Distribution... 

We consider the expression of the lab frame photoelectron angular distribution for a randomly oriented molecular sample. The frozen core, electric dipole approximation for the differential cross-section for electron emission into a solid angle about a direction k can be written as... 

J. Cooper and R. N. Zare, Photoelectron angular distributions. In Sydney Geltman, KalayanaT. Mahanthappa, and Wesley Emil Brittin (ed.). Lectures in theoretical physics Vol. 11c. Atomic collision processes, Gordon and Breach, New York, 1969, pp. 317—337. 

Most of the theoretical work regarding the utility of time-resolved photoelectron angular distributions to probe electronic, vibrational, and rotational dynamics have also concerned neutral photoionization.(Adapted from Sanov, 2002)... 

Several reasons have been put forward to explain the change in the angular intensity pattern of the photoelectrons. One explanation is that intermediate neutral energy levels are ac-Stark shifted into resonance and contribute new selection rules to the photoionization process [53,54], Another possibility is that the electrons of the Kr or D2 are driven into the core Kr+ or D2 in a scattering-like process that creates interference fringes in the photoelectron angular distribution due to interference between multiple scattering channels [55],... 

Figure 5.13 Helium photoelectron angular distribution in the He+(2p) channel (logarithmic scale). x-Axis cosine of the electron ejection angle relative the laser polarization, y-axis total energy (1 a.u. 27 eV). (a) After the XUV-pulse after the IR-pulse for three different time delays, separated from each other by half the IR-pulse period, 15.53 fs (b), 16.87 fs(c), and 18.21 (d). The fringes in (b)-(d) arise due to the interference between the (XUV-pulse) direct ionization from the ground state and the (IR-pulse) ionization from the doubly excited populated by the XUV-pulse.

In this equation, the spherical angles 6 and

defined relative to the photon momentum k, photoelectron momentum p, and photon polarization vector e, as indicated in Figure 1, fi i is a dipole photoelectron angular distribution parameter, yni and Sni are nondipole photoelectron angular distribution parameters. 

Both models demonstrate sizable oscillations, i.e., confinement resonances, in the energy dependence of photoelectron angular distribution parameters. The resonances fade away rapidly with an increasing energy of the photoelectrons. The decrease in the resonance amplitudes with increasing... 

The discovery of confinement resonances in the photoelectron angular distribution parameters from encaged atoms may shed light [36] on the origin of anomalously high values of the nondipole asymmetry parameters observed in diatomic molecules [62]. Following [36], consider photoionization of an inner subshell of the atom A in a diatomic molecule AB in the gas phase, i.e., with random orientation of the molecular axis relative to the polarization vector of the radiation. The atom B remains neutral in this process and is arbitrarily located on the sphere with its center at the nucleus of the atom A with radius equal to the interatomic distance in this molecule. To the lowest order, the effect of the atom B on the photoionization parameters can be approximated by the introduction of a spherically symmetric potential that represents the atom B smeared over... 

Figure 27 Relativistic RPAE calculated results [30] of the 6s dipole photoelectron angular distribution parameter j06s(eo) from free Hg and <3>Hg, The RRPA calculations included interchannel coupling...

Figure 28 Relativistic RPAE calculated results [30] of the 6s dipole photoelectron angular distribution parameter of Hg at two different levels of truncation with regard to RRPA interchannel coupling (a) including channels from the 6s2 subshell alone, Aa, and (b) including channels from the 6s2 and 5d10 subshells of d>Hg, as in Figure 27. Confinement effects were accounted for in the A-potential model at the frozen-cage approximation level.

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