Abstract
Two-photon ionization of atomic hydrogen with an excess photon is revisited. Thenon-relativistic dipole approximation and Coulomb Green function (CGF)formalism are applied. Using the CGF Sturmian expansion straightforwardly, onegets the radial transition amplitude in the form of an infinite sum over Gausshypergeometric functions which are polynomials. It is convergent if allintermediate states are in the discrete spectrum. In the case of two-photonionization with an excess photon, when photoionization is also possible,intermediate states are in the continuum. We performed the explicit summationover intermediate states and got a simple general expression for the radialtransition amplitude in the form of a finite sum over Appell hypergeometricfunctions, which are not polynomials. An Appell function may be expressed as aninfinite sum over Gauss functions. In the case of ionization by an excess photon,Gauss functions are transformed to give a convergent radial transitionamplitude for the whole region. The generalized cross sections for two-photonabove-threshold ionization of atomic hydrogen in the ground state and excitedstates calculated by us agree very well with results of previous calculations.Generalized cross sections for two-photon ionization of positronium in theground state are obtained by scaling those for atomic hydrogen.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Journal of Physics B: Atomic, Molecular and Optical Physics
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
