Absorption spectra of azobenzenes simulated with time-dependent density functional theory

✍ Scribed by Denis Jacquemin; Julien Preat; Eric A. Perpète; Daniel P. Vercauteren; Jean-Marie André; Ilaria Ciofini; Carlo Adamo

• Publisher: John Wiley and Sons
• Year: 2011
• Tongue: English
• Weight: 253 KB
• Volume: 111
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/qua.22910

✦ Synopsis

Abstract

Using time‐dependent density functional theory and the polarizable continuum model, we have simulated the absorption spectra of an extended series of azobenzene dyes. First, we have determined a theoretical level optimal for this important class of dyes, and it turned out that a C‐PCM‐CAM‐B3LYP/6‐311+G(d,p)//C‐PCM‐B3LYP/6‐311G(d,p) approach represents an effective compromise between chemical accuracy and computational cost. In a second stage, we have compared the theoretical and experimental transition energies for 46 n → π^☆^ and 141 π → π^☆^ excitations. For the full set, that spans over a 302–565 nm domain, we obtained a mean absolute deviation of 13 nm (0.10 eV) and a linear correlation coefficient of 0.95, illustrating the accuracy of our approach, though some significant outliers pertained. In a last step, the impact of several modifications, that is, trans/cis isomerization, variation of the acidity of the medium and azo/hydrazo tautomerism have been modeled with two functionals. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010