Electronic excitation of sulfur-organic compounds - performance of time-dependent density functional theory

Abstract

To de®ne the scope and limitations of the time-dependent density functional theory (TDDFT) method, spectral absorption data of a series of about 100 neutral or charged sulfur-organic compounds with up to 24 non-hydrogen atoms and up to four sulfur atoms were calculated in the near-UV, visible and IR regions. Although the theoretical vertical transition energies correspond only approximately to experimental absorption band maxima, the mean absolute deviation was calculated to be 0.21 eV (1600 cm )1 ). The main absorption features of various compounds with monocoordinated or dicoordinated sulfur atoms are well reproduced. As far as possible TDDFT results were compared with those of semiempirical Zerner's intermediate neglect of dierential overlap (ZINDO/S) and of Pariser±Parr±Pople (PPP) calculations. TDDFT also works well in cases where the semiempirical methods fail. Limitations of TDDFT were encountered with calculations of spectral absorptions of dye molecules. The``vinylene shift'' of polymethine dyes is not reproduced by TDDFT. Whereas electronic excitation energies delocalized polar and betainic chromophores are reasonably well reproduced, excitation energies of charge-transfer-type and charge-resonance-type transitions of weakly interacting composite chromophores are signi®cantly underestimated.

Femtosecond time-resolved electronic relaxation dynamics in tetrathiafulvalene

“…By TD-DFT calculations converging to a C 2v boat geometry, Fabian assigned the weak absorption band around 368 nm to A 1 → B 1 transition (π → π * along x) and found only one state lying in the intense double structure (303/317 nm) corresponding to A 1 → B 2 transition (π → π * along y). 30 The oscillator strengths calculated by this TD-DFT study at 368 nm and ≈307 nm are very similar, which goes strongly against the experimental observations. [17][18][19][20] Andreu et al, as well by TD-DFT calculations still in C 2v symmetry, assigned the two most intense excitations to the 1 1 B 2 state transition at 317 nm and the 2 1 B 1 state transition at 303 nm.…”

Computational Molecular Electronic Spectroscopy with TD-DFT

“…Indeed, the TD-DFT transition energies are too large (by ca. 0.3-1.0 eV) in cyanines, and this conclusion has been reached through comparisons of both TD-DFT's E vertÀa with their highlycorrelated wavefunction counterparts [82,87] and TD-DFT's E AFCP with experimental references for fluoroborate emitters [88,89]. More puzzling is the fact that the errors seem to be almost independent of the selected XCF and that this error is not related to a multi-determinant nature.…”

“…Both the canonical streptocyanines and the fluoroborate dyes (e.g., boron-dipyrromethene, BODIPY) belong to that class and it has been shown that they can hardly be modeled with adiabatic TD-DFT [33,[82][83][84][85][86][87][88][89][90][91][92][93]. Indeed, the TD-DFT transition energies are too large (by ca.…”

Structural and solvent effects on the spectroscopic properties of 1, 8‐naphthalimide derivatives: A density functional study

“…These data show that they are rather comparable to the experimental values. TD‐PBE1PBE is better than the inspection of TD‐B3LYP/6‐31G* approach having a deviation of about 0.25 eV41. Figure 3 also shows that the emission spectra are underestimated, which is partly because of the neglect of the electron correlation of CIS approaches and its optimized structure in gas phase.…”