Dresden 2006 – scientific programme

Parts | Days | Selection | Search | Downloads | Help

O: Oberflächenphysik

O 12: Methods

O 12.4: Talk

Monday, March 27, 2006, 15:45–16:00, WIL B321

How the solid state matrix affects the chemical shift of core-level binding energies: A novel method to take the induction effect into account — •Kunyuan Gao, Thomas Seyller, and Lothar Ley — Institut für Physik der Kondensierten Materie, Lehrstuhl für Technische Physik, Universität Erlangen-Nürnberg, Erwin-Rommel-Str. 1, D-91058 Erlangen, Germany

Small binding energy variations of core levels, i.e., chemical shifts provide useful information about the chemical environment of the atom under investigation. With the widespread use of synchrotron radiation as excitation source for photoelectron spectroscopy a vastly improved spectral resolution compared to conventional laboratory sources allows the unambiguous identification of components with chemical shifts less than a tenth of an eV. As a consequence, the interpretation of the chemical shift in complex systems such as mixed oxides requires to take charge transfer beyond the first coordination shell into account. A novel scheme is presented that allows to include these so-called induction effects in estimates of chemical shifts based on the electronegativities of the constituent elements. The method is a judicious extension of Sanderson’s original approach [1] towards network structures. At each point of departure from Sanderson, the method is tested successfully against the rigorous Sanderson formalism. For three crucial examples of relevance in semiconductor technology, our new method yields predictions in excellent agreement with experiment. [1] R.T. Sanderson, Chemical Bonds and Bond Energy, Academic Press, London, 1971, p.17.