Issue 4, 2011

Electronic structure and optical spectra of catechol on TiO2nanoparticles from real time TD-DFT simulations

Abstract

The electronic structure and the optical response of free catechol, [Ti(cat)3]2 complex, and catechol bound to TiO2 nanoclusters have been analysed using time dependent density functional theory (TD-DFT) performing calculations both in real time and frequency domains. Both approaches lead to similar results providing the basis sets and functionals are similar. For all cases, the simulated spectra agree well with the experimental ones. For the adsorption systems, the spectra show a band at 4.7 eV associated to intramolecular catechol π → π* transitions, and low energy bands corresponding to transitions from catechol to the cluster with a tail that is red-shifted when the coupling between the dye and the cluster is more effective. Thus, dissociative adsorption modes provide longer tails than the molecular mode. Although the bidentate complex is more stable than the monodentate, the energy difference between both is smaller when the cluster size increases. Small cluster models reproduce the main features of the optical response, however, the (TiO2)15 cluster constitutes the minimal size to provide a complete picture. In this case, the conventional TD-DFT (frequency domain) calculations are highly demanding computationally, while real time TD-DFT is more efficient and the calculations become affordable.

Graphical abstract: Electronic structure and optical spectra of catechol on TiO2 nanoparticles from real time TD-DFT simulations

Supplementary files

Article information

Article type
Paper
Submitted
17 Jun 2010
Accepted
25 Oct 2010
First published
25 Nov 2010

Phys. Chem. Chem. Phys., 2011,13, 1506-1514

Electronic structure and optical spectra of catechol on TiO2 nanoparticles from real time TD-DFT simulations

R. Sánchez-de-Armas, M. A. San-Miguel, J. Oviedo, A. Márquez and J. F. Sanz, Phys. Chem. Chem. Phys., 2011, 13, 1506 DOI: 10.1039/C0CP00906G

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