TIME DEPENDENT DENSITY FUNCTIONAL THEORY ... - TDDFT.org

Hartree Fock exchange in Time Dependent
Density Functional Theory
Leonardo Bernasconi ⋆ , Michiel Sprik ⋆ , and Jürg Hutter †
⋆ Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
† Physical Chemistry Institute, University of Zurich, Winterthurerstrasse, 190, CH-8057 Zurich,
Switzerland
The absorption spectrum of acetone in aqueous solution at finite temperature is computed using
Time Dependent Density Functional Theory and Car Parrinello Molecular Dynamics at the BLYP,
B3LYP and PBE0 level of theory. The role of the exchange-correlation functional in separating
spectral features originating from localised (intra-molecular) and charge-transfer or collective electronic
excitations is analysed. In the limit of local and frequency independent exchange-correlation
kernels, admixture of Hartree Fock exchange in the density functional is proved to be a necessary
requirement in order to remove the unphysical degeneracy between the intra-molecular n→ π ∗
and solvent→solvent transitions. Results for the n→ π ∗ transition energy, oscillator strength and
solvatochromic shift are computed in excellent agreement with experiment.
1. J. Hutter, J. Chem. Phys. 118, 3928 (2003).
2. L. Bernasconi, M. Sprik, and J. Hutter, J. Chem. Phys. 119, 12417 (2003).
4. L. Bernasconi, M. Sprik, and J. Hutter, Chem. Phys. Lett. (2004, to be published).
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