Figure compares the absorption and emission lineshapes generated using the three E-FC methods. All three methods show good agreement for the absorption lineshape and similar FWHM (∼0.490 eV) but remain underestimated in width relative to the experiment. For the emission lineshapes, both E opt -avg 10 FTFC and E-sum 100 FTFC show good agreement with each other, with E-sum 100 FTFC producing a more narrow spectrum (FWHM is 0.585 eV for E-sum 100 FTFC, 0.653 eV for E opt -avg 10 FTFC), whereas the emission spectrum of the E-avg 10 ZTFC method is wider and jagged because of the large distribution of VDEs, leading to an overly large FWHM value of 0.779 eV. Unlike NBD, this overly large broadening appears to be completely dominated by chromophore flexibility. About 33% of emission lineshapes have an FWHM of more than 0.7 eV, and these are the snapshots where the pyrone ring is no longer planar. As shown in Table , the predicted Stokes shift is underestimated by all three methods.