Prediction of charge-transfer excitations in coumarin-based dyes using a range-separated functional tuned from first principles.
We study the description of charge-transfer excitations in a series of coumarin-based donor-bridge-acceptor dyes. We show that excellent predictive power for the excitation energies and oscillator strengths in these systems is obtained by using a range-separated hybrid functional within the generalized Kohn-Sham approach to time-dependent density functional theory. Key to this success is a step for tuning the range separation parameter from first principles. We explore different methods for this tuning step, which are variants of a recently suggested approach for charge-transfer excitations [T. Stein et al., J. Am. Chem. Soc. 131, 2818 (2009)]. We assess the quality of prediction by comparing to excitation energies previously published for the same systems using the approximate coupled-cluster singles and doubles (CC2) method.
Stein
Tamar
T
Fritz Haber Center for Molecular Dynamics, Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Kronik
Leeor
L
Baer
Roi
R