DFT modeling of band shifts and widths in the absorption spectrum of a 9‐(diphenylamino)acridine/silica receptor center upon its interaction with gas‐phase NH3, C2H5OH, and (CH3)2CO molecules

Abstract

AbstractThe interaction of small analyte molecules (NH3, C2H5OH, and (CH3)2CO) in the gas phase with the 9‐(diphenylamino)acridine dye adsorbed on an amorphous silica surface is studied by density functional theory (DFT) calculations using the cluster approach. Two cluster models for the silica surface are considered: a small SiH3OH model and an extended Si10O11(OH)18 one, constructed using classical molecular dynamics simulations. The electronic absorption spectra of the adsorbed dye are calculated within the time‐dependent density functional theory (TDDFT) formalism and the effects of dye–analyte interactions are investigated. The spectral line broadening due to vibrations is estimated within the Pekar model. A computationally efficient procedure is proposed for the prediction of changes in the absorption spectra of organic dyes adsorbed on silica on their interaction with analytes. © 2012 Wiley Periodicals, Inc.