title: Rates of exponential decay in systems of discrete energy levels by Stieltjes imaging.
abstract: An isolated bound state coupled to a continuum shows an exponential decay of its survival probability. Rates of the exponential decay occurring due to the bound-continuum coupling can be recovered from discretized continuum (L(2)) calculations using a computational technique known as Stieltjes-Chebyshev moment theory or Stieltjes imaging. At the same time, some genuinely discrete level systems, e.g., Bixon-Jortner model, also show an exponential (or approximately exponential) decay of the initially populated level before the onset of quantum revivals. Here, we demonstrate numerically that Stieltjes imaging can be used for calculation of the rates of the exponential decay in such discrete level systems. We apply the Stieltjes imaging technique to the approximately exponential decay of inner-valence vacancies in trans-butadiene in order to show that the breakdown of the molecular orbital picture of ionization in the inner valence region can be physically interpreted as an energy-forbidden Coster-Kronig transition.
authors.affiliation: Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom.
authors.forename: Jacob
authors.initials: J
authors.lastname: Craigie
authors.affiliation: Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom.
authors.forename: Ali
authors.initials: A
authors.lastname: Hammad
authors.affiliation: Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom.
authors.forename: Bridgette
authors.initials: B
authors.lastname: Cooper
authors.affiliation: Department of Physics, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom.
authors.forename: Vitali
authors.initials: V
authors.lastname: Averbukh