Ab initio calculation of interatomic decay rates of excited doubly ionized states in clusters

Abstract

Recently, a computational technique for ab initio calculation of the inter-atomic and intermolecular non-radiative decay processes has been developed [1]. It combines the Fano formalism with the Green's function method known as the algebraic diagrammatic construction. The problem of normalization of continuum wave functions stemming from the use of the Gaussian basis sets is solved by using the Stieltjes imaging technique. In the present paper, the methodology is extended in order to describe the inter-atomic decay of excited doubly ionized states of clusters. The new computational scheme is applied to compute the inter-atomic decay rates of doubly ionized states formed by Auger relaxation of core vacancies in NeAr and MgNe van der Waals clusters.

The role of metal ions in X-ray-induced photochemistry

“…Within this ab initio approach the bound and continuum parts of the decaying state are constructed by means of the ADC(2)-extended scheme for the one-particle and two-particle propagator, respectively [4,5]. The renormalisation of the pseudocontinuum generated by the ADC scheme in an L 2 basis is done by the Stieltjes imaging technique [6].…”

“…The X-ray absorption spectroscopy of transition metal complexes in solutions offers a glimpse at the transformations accompanying the interaction of X-rays with the metal. The metal ion may become oxidised, reduced or even remain unaltered [5,6]; the particular outcome depends on the initial metal charge and the nature of ligands. Ample evidence from a different field, that of the X-ray crystallography, demonstrates that the radiation damage inflicted on a sample is highly non-random [7].…”

Collective Interatomic Decay of Multiple Vacancies in Clusters

“…[8]). Far more accurate decay widths can be obtained by the Fano-ADC technique, first developed for the decay of singly ionized states [8] and very recently generalized for the doubly ionized [16] systems. Fano-ADC approach for electronic decay widths is an L 2 method that is based on the Fano expression [17] for Γ through the matrix element of the full Hamiltonian (Ĥ) between the bound-like (Φ) and the continuum-like (χ α,εα ) components of the wave function at the energy of the resonance (E r ):…”

Collective relaxation processes in atoms, molecules and clusters

“…Despite being the only radiationless decay mode, however, collective ICD can be quenched by dissociative nuclear dynamics of the multiply ionized cluster. In order to assess the feasibility of this higher-order process, Averbukh and Kolorenč [19] studied the competition between electronic decay and cluster disintegration in the specific example of a Kr 2 Ar trimer using the Fano-ADC method [90] for the decay widths and simulation of the wave packet evolution on complex potentials. At the equilibrium geometry, the calculated collective decay width is 2 meV.…”

“…Using the ab initio Fano-ADC method [90] they calculated CAD lifetimes for a few such double vacancy states in small molecular species. The results range from 13 fs for the F 2 molecule down to 1.1 fs for the double O 2s hole in the OH − molecular anion.…”