Table‐CI with macroconfiguration approach for describing electronic states of molecules in intense radiation fields

Abstract

ABSTRACT:Modifications to the recently introduced table-driven multireference configuration interaction (CI) approach that uses macroconfigurations necessary for the efficient construction of electronic Floquet states are described. Adiabatic electronic Floquet states have recently shown promise as simplifying the description of the electronic structure of molecules in intense radiation fields. The algorithm for the tabledriven multireference CI approach that uses macroconfigurations for the calculation of electronic energies needs two principal modifications to extend use to the calculation of Floquet states. First, it must be possible to calculate electronic states of several irreducible representations of the molecular point group simultaneously. Second, matrix elements of the electronic dipole operator are required. It is demonstrated that the modifications that enable these capabilities are possible and in fact do not lessen the high computational efficiency of the energy algorithm. The modifications are described in sufficient detail, with appropriate formulas, to facilitate implementation. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem 105: [921][922][923][924][925][926][927][928] 2005

An Iterative Ab Initio Non-Hermitian Floquet Method for Photoionization Resonances

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Theoretical study of electronic states of N22+ in an intense radiation field

“…It has recently been shown that the task of calculating electronic Floquet states is amenable to high accuracy methods in modern quantum chemistry, and a variant of the multireference configuration interaction method with single and double excitations ͑MRCISD͒ from a set of reference configurations was introduced for its solution. 6,7 The developed MRCISD-based description of Floquet states was successfully demonstrated on studying the behavior of the lowest six doublet electronic states of Li 2 + in an intense ͑0.9 ϫ 10 12 W/cm 2 ͒ field. 6 In the present work, using the same method, we study the Floquet states of N 2 2+ created by the interactions of the six lowest singlet ͑1 1 ⌺ g + , 1 1 ⌬ g , 2 1 ⌺ g + , 1 1 ⌸ u , 1 1 ⌸ g , and 1 1 ⌺ u − ͒ states of the dication, which correlate with its lowest dissociation asymptote 2N + ͑ 3 P g ͒, in an intense ͑0.4ϫ 10 13 W/cm 2 ͒ radiation field.…”