 
Summary: Electrical response of molecular chains in density functional theory:
Ultranonlocal response from a semilocal functional
R. Armiento, S. Kümmel, and T. Körzdörfer
Theoretische Physik, Universität Bayreuth, D95440 Bayreuth, Germany
Received 28 September 2007; published 2 April 2008
An exchange potential functional is constructed from semilocal quantities and is shown to reproduce
hydrogen chain polarizabilities with the same accuracy as exact exchange methods. We discuss the exchange
potential features that are essential for accurate polarizability calculations, i.e., derivative discontinuities and
the potential step structure. The possibility of a future generalization of the methods into a complete semilocal
exchangecorrelation functional is discussed.
DOI: 10.1103/PhysRevB.77.165106 PACS number s : 31.15.E , 36.20. r, 71.15.Mb, 72.80.Le
I. INTRODUCTION
Molecular chains can have a large linear and nonlinear
electrical response, while being both cheap to produce and
easy to process. This makes them interesting for industrial
use for, e.g., nonlinear optics devices.1
However, no large
scale computationally feasible electronic structure theory
currently gives an all around good description of the proper
ties of these systems.
