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ABSTRACT
Recent developments toward the production and laboratory use of pulses of high intensity, and/or of very high frequency, and/or of ultrashort duration, make possible experiments which can produce time-resolved data on ultrafast transformations involving ‘motions’ of electrons.
The formulation, quantitative understanding and prediction of related new phenomena entail the possibility of computing and applying solutions of the many-electron time-dependent Schrödinger equation, for arbitrary electronic structures, including the dominant effects of Rydberg series, of multiply excited states and of the multi-channel continuous spectrum. To this end, we have proposed and applied to many prototypical cases the state-specific expansion approach (SSEA).
The paper explains briefly the SSEA and outlines four of its applications to recently formulated problems concerning time-resolved electronic processes, where electron correlations are crucial. These are as follows: (1) the time resolution of the decay of polyelectronic unstable states, (2) the excitation and decay of strongly correlating doubly excited states and atto-time-resolution of their geometries, (3) the time-resolved process of formation of the interference profiles of resonance states during the femtosecond photoionisation of helium and aluminium, and (4) the relative time delay in the (2s, 2p) photoionisation of neon by an attosecond pulse.
Disclosure statement
No potential conflict of interest was reported by the author.