Solvent-Induced Shift of the Lowest Singlet pi -> pi* Charge-Transfer Excited State of p-Nitroaniline in Water: An Application of the TDDFT/EFP1 Method

TitleSolvent-Induced Shift of the Lowest Singlet pi -> pi* Charge-Transfer Excited State of p-Nitroaniline in Water: An Application of the TDDFT/EFP1 Method
Publication TypeJournal Article
Year of Publication2011
AuthorsSok S, Willow SY, Zahariev F, Gordon MS
Journal TitleJournal of Physical Chemistry A
Volume115
Pages9801-9809
Date Published09
Type of ArticleArticle
ISBN Number1089-5639
Accession NumberWOS:000294385800004
Keywordsab-initio, density-functional theory, dipole-moments, electronic-spectra, fragment potential method, ground-state, model, molecular-dynamics, ORGANIC-MOLECULES, simulations, solvation
Abstract

The combined time-dependent density functional theory effective fragment potential method (TDDFT/EFP1) is applied to a study of the solvent-induced shift of the lowest singlet pi -> pi* charge-transfer excited state of p-nitroaniline (pNA) from the gas to the condensed phase in water. Molecular dynamics simulations of pNA with 150 EFP1 water molecules are used to model the condensed-phase and generate a simulated spectrum of the lowest singlet charge-transfer excitation. The TDDFT/EFP1 method successfully reproduces the experimental condensed-phase pi -> pi* vertical excitation energy and solvent-induced red shift of pNA in water. The largest contribution to the red shift comes from Coulomb interactions, between pNA and water, and solute relaxation. The solvent shift contributions reflect the increase in zwitterionic character of pNA upon solvation.

DOI10.1021/jp2045564
Alternate JournalJ. Phys. Chem. A