Compact representation of generalized molecular polarizabilities and
efficient calculation of polarization energy in an arbitrary electric
field
Abstract
Generalized polarizabilities and the molecular charge distribution can
describe the response of a molecule in an arbitrary static electric
field up to second order. Depending on the expansion functions used to
describe the perturbing potential, the generalized polarizability matrix
can have rather large dimension (~1000). This matrix is
the discretized version of the density response function or electronic
susceptibility. Diagonalizing and truncating it can lead to significant
(over an order of magnitude) speed-up in simulations. We have analyzed
the convergence behavior of the generalized polarizability using a plane
wave basis for the potential. The eigenfunctions of the generalized
polarizability matrix are the natural polarization potentials. They are
potentially useful to construct efficient polarizability models for
molecules.