Solvent-Induced Shifts in Electronic Spectra of Uracil

TitleSolvent-Induced Shifts in Electronic Spectra of Uracil
Publication TypeJournal Article
Year of Publication2011
AuthorsDeFusco A, Ivanic J, Schmidt MW, Gordon MS
Journal TitleJournal of Physical Chemistry A
Date Published05/12
Type of ArticleArticle
ISBN Number1089-5639
Accession NumberISI:000290126900002
KeywordsAQUEOUS-SOLUTION, configuration-interaction, conical intersections, distributed, excited-state dynamics, fragment potential method, initio molecular-dynamics, multipole analysis, nucleic-acid bases, perturbation-theory, reaction field-theory

Highly accurate excitation spectra are predicted for the low-lying n-pi* and pi-pi* states of uracil for both the gas phase and in water employing the complete active space self-consistent field (CASSCF) and multiconfigurational quaside-generate perturbation theory (MCQDPT) methods. Implementation of the effective fragment potential (EFP) solvent method with CASSCF and MCQDPT enables the prediction of highly accurate solvated spectra, along with a direct interpretation of solvent shifts in terms of intermolecular interactions between solvent and solute. Solvent shifts of the n-pi* and pi-pi* ye excited states arise mainly from a change in the electrostatic interaction between solvent and solute upon photoexcitation. Polarization (induction) interactions contribute about 0.1 eV to the solvent-shifted excitation. The blue shift of the n-pi* state is found to be 0.43 eV and the red shift of the pi-pi* state is found to be -0.26 eV. Furthermore, the spectra show that in solution the pi-pi* state is 0.4 eV lower in energy than the n-pi* state.

URL<Go to ISI>://000290126900002
Alternate JournalJ. Phys. Chem. A