title: B-spline algebraic diagrammatic construction: application to photoionization cross-sections and high-order harmonic generation.
abstract: We present the first implementation of the ab initio many-body Green's function method, algebraic diagrammatic construction (ADC), in the B-spline single-electron basis. B-spline versions of the first order [ADC(1)] and second order [ADC(2)] schemes for the polarization propagator are developed and applied to the ab initio calculation of static (photoionization cross-sections) and dynamic (high-order harmonic generation spectra) quantities. We show that the cross-section features that pose a challenge for the Gaussian basis calculations, such as Cooper minima and high-energy tails, are found to be reproduced by the B-spline ADC in a very good agreement with the experiment. We also present the first dynamic B-spline ADC results, showing that the effect of the Cooper minimum on the high-order harmonic generation spectrum of Ar is correctly predicted by the time-dependent ADC calculation in the B-spline basis. The present development paves the way for the application of the B-spline ADC to both energy- and time-resolved theoretical studies of many-electron phenomena in atoms, molecules, and clusters.
authors.affiliation: Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Ruberti
authors.affiliation: Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom.
authors.forename: V
authors.initials: V
authors.lastname: Averbukh
authors.affiliation: Dipartimento di Scienze Chimiche, Universita' di Trieste, Via Giorgieri 1, I-34127 Trieste, Italy.
authors.forename: P
authors.initials: P
authors.lastname: Decleva