Optical Absorption of Water: Coulomb Effects versus Hydrogen Bonding

P. H. Hahn, W. G. Schmidt, K. Seino, M. Preuss, F. Bechstedt, and J. Bernholc

Phys. Rev. Lett. 94, 037404 – Published 27 January 2005

Abstract

The optical spectrum of water is not well understood. For example, the main absorption peak shifts upwards by 1.3 eV upon condensation, which is contrary to the behavior expected from aggregation-induced broadening of molecular levels. We investigate theoretically the effects of electron-electron and electron-hole correlations, finding that condensation leads to delocalization of the exciton onto nearby hydrogen-bonded molecules. This reduces its binding energy and has a dramatic impact on the line shape. The calculated spectrum is in excellent agreement with experiment.

Received 3 October 2004

DOI:https://doi.org/10.1103/PhysRevLett.94.037404

Authors & Affiliations

P. H. Hahn and W. G. Schmidt

Institut für Festkörpertheorie und -optik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany, and Center for High Performance Simulation and Department of Physics, North Carolina State University, Raleigh, North Carolina 27695-8202, USA

K. Seino, M. Preuss, and F. Bechstedt