Photoelectron angular distribution dynamics

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)... 

Even more recently, the experimental resolution has been still further enhanced, and both partial cross sections and photoelectron angular distributions have been determined [332]. The data shown provide fine examples of interfering autoionising resonances (see chapter 8) and have been analysed in remarkable detail using the hyperspherical close-coupling method they represent a critical test of the dynamics of double excitation in He. 

As will be seen in Chapter 8, equations identical to Eq. (7.2.13) and Eq. (7.2.17) describe the photoelectron angular distributions observed in photoionization processes. However, owing to the difference in photofragment masses (atom vs. electron), the photoelectron angular distributions sample the photofragmentation dynamics very differently from photodissociation angular distributions. 

In conclusion, photoelectron angular distributions not only provide insightful fingerprints of vibrational wavepacket dynamics, but their strong... 

Photoelectron angular distributions reflecting the controlled dynamics... 

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. 

A detailed derivation of the photoionization differential cross-section expression, leading ultimately to the angular distribution in Eq. (4), is provided in Appendix A. This will help provide a detailed understanding of the photoelectron dynamics that determine the angular distribution parameters, as will be discussed in a subsequent section, but for now it may help develop the reader s appreciation of this phenomenon to provide a simple, if necessarily inexact, mechanical analogy. 

In conventional photoelectron spectroscopy, angular distributions are known to provide valuable insight into the underlying dynamics. A few groups have, moreover, recently reported measurements of angular distributions in pump-probe photoelectron spectra [332, 406]. Althorpe and Sei-deman have also examined the angular distributions of photoelectrons in the pump-probe ionization for a rigid diatomic molecule NO [8]. 

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