STURMIAN APPROACH TO EXTRACT TRANSITION AMPLITUDES IN SCATTERING PROBLEMS WITH NONDECAYING SOURCES

A.I. GOMEZ, G. GASANEO, D.M. MITNIK, M.J. AMBROSIO AND L.U. ANCARANI

Buenos Aires

Congreso; Molecular Electronic Structure MESBA 2016; 2016

IAFE

progress in attosecond physics mainly becauseof the fast experimental development of ultrafastlasers, which enabled the temporal study ofdynamical processes at the natural atomic timescale. In turn, this led to the development oftheoretical and computational methods to studyultrafast phenomena with high resolution in thetime domain. This implies solving the timedependent Schr¨odinger equation (TDSE). Theone?photon double ionization process is considereda closed business, inasmuch as full agreementhas been obtained between theory and experiments.On the other hand, the two-photoncase is far more difficult to deal with, especiallyexperimentally, due to the weak two-photon ionizationyield. Non-sequential two-photon doubleionization (TPDI) of helium is the simplest systemfor which such process occurs. It has beenstudied extensively during the last decade, boththeoretically [1] and experimentally [2]. Nevertheless,there are still large discrepancies betweenthe different theoretical approaches and,as such, the process is not considered to be fullyunderstood.In this work we use the Generalized SturmiansFunctions (GSF) method [3] to solve thetwo?photon ionization of Hydrogen, taken asa benchmark case to study the non?sequentialtwo?photon double ionization of atoms. Theoretically,major difficulties arise in this kind ofproblems: the imposition of adequate asymptoticconditions and the way to extract scatteringamplitudes, specially for those cases forwhich the source does not vanish at large distances.The aim of this contribution is to showhow these difficulties can be easily dealt withusing the GSF method.