Theory of interatomic (intermolecular) Coulombic decay in clusters

• Applicant: Professor Dr. Lorenz S. Cederbaum
• Subject Area: Theoretical Chemistry: Electronic Structure, Dynamics, Simulation
• Term: from 2005 to 2011
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 19146214

• Final Report Year: 2012

Final Report Abstract

In this project we investigated interatomic Coulombic decay (ICD) an ultrafast relaxation process of excited electronic states operative in a medium. The numerical methods were developed and implemented for accurate ab initio calculations of ICD rates. The development of these methods allowed us to study previously inaccessible aspects of ICD. Thus, this decay pathway was investigated in larger systems such as endohedral fullerenes and He droplets. The discovered dramatic increase in decay rates with the number of neighbours establishes ICD as an important relaxation process in a medium and underlies the necessity of taking it into account in analysing photoelectron spectra of clusters and condensed media. In addition the knowledge of accurate ICD rates made it possible to account for the effects of nuclear dynamics on ICD electron spectra which is the main measurable characteristic of this process. We also established that ICD is not only confined to relaxation of inner-valence ionised states, but is also the leading relaxation pathway of inner- and outer-valence excited states or doubly ionised states formed in the Auger decay. In the study of the Auger-ICD cascade we were particularly motivated by the importance of Auger process as the method of chemical analysis and its role in DNA degradation mechanisms. The investigation of this cascade in small rare gas clusters done hand in hand with the experimental groups has paved the way for its study in the systems of more immediate import for biology. We hope that the methodological advances and better understanding of ICD mechanism achieved in this project will stimulate future studies of this important effect.

Publications

• Ab initio calculation of interatomic decay rates by a combination of the Fano ansatz, Green’s-function methods, and the Stieltjes imaging technique. J. Chem. Phys. 123, 204107 (2005)
  V. Averbukh and L. S. Cederbaum
  
• Interatomic decay of innervalence-excited states in clusters. J. Chem. Phys. 124, 144315 (2006)
  K. Gokhberg, V. Averbukh, and L. S. Cederbaum
  
• Interatomic Electronic Decay in Endohedral Fullerenes. Phys. Rev. Lett. 96, 053401 (2006)
  V. Averbukh and L. S. Cederbaum
  
• High activity of helium droplets following ionisation of systems inside those droplets. Phys. Rev. B 76, 094513 (2007)
  N. V. Kryzhevoi, V. Averbukh, L. S. Cederbaum
  
• On the doubly ionized states of Ar2 and their intra- and interatomic decay to Ar32+. J. Chem. Phys. 128, 014307 (2008)
  S. D. Stoychev, A. I. Kuleff, F. Tarantelli, and L. S. Cederbaum
  
• Recoil by Auger electrons: Theory and application. J. Chem. Phys. 131, 164301 (2009)
  P. V. Demekhin, S. Scheit, L. S. Cederbaum