Some recently found interchannel coupling effects in atomic photoionization processes

Abstract

The present article highlights some recently found interchannel coupling effects that must be taken into account to explain an atomic photoabsorption process. The importance of interchannel coupling effects is illustrated in a few select cases of recent interest: (a) sustenance of interchannel coupling effects at photon energies high enough where the independent particle approximation was believed to hold good; (b) demonstration of the generality of a new spin–orbit activated correlation effect as an essentially many-body collective event; (c) recognition of the scope and limitations of the indispensable approximation techniques to account for each ‘kind’ of correlation effect in configuration interactions between ‘discrete’ and ‘continuum’ channels; and (d) the recognition in some recent studies on atomic mercury, that contrary to the earliest expectations, dynamical interchannel coupling between dipole and quadrupole channels is important as found in the studies of photoionization of atomic xenon as well.