Effects of conjugation in length and dimension on spectroscopic properties of fluorene-based chromophores from experiment and theory.
A series of one-photon absorption spectra for fluorene-based donor-pi-acceptor molecules is presented and spectroscopically assigned, based upon the results obtained from time-dependent density functional theory. The computed excitation energies were generally shown to be in good agreement with experiment, particularly when compared to results from measurements carried out in a nonpolar solvent, which were available for some molecules. The computed oscillator strengths may resolve discordant experimental values in some cases, for example, for AF-380, AF-270, and AF-295. However, a quantitative comparison between computed and observed oscillator strengths is complicated by band overlapping. Thus, the computed extinction coefficients obtained by summing over the Gaussian bands are useful in such cases.
Nguyen
Kiet A
KA
Materials and Manufacturing Directorate, Air Force Research Laboratory, Wright Patterson Air Force Base, Ohio 45433, USA. Kiet.Nguyen@wpafb.af.mil
Rogers
Joy E
JE
Slagle
Jonathan E
JE
Day
Paul N
PN
Kannan
Ramamurthi
R
Tan
Loon-Seng
LS
Fleitz
Paul A
PA
Pachter
Ruth
R