Vibronic bandshape of the absorption spectra of dibenzoylmethanatoboron difluoride derivatives: analysis based on ab initio calculations

Abstract

The nature of absorption bandshapes of dibenzoylmethanatoboron difluoride (DBMBF2) dye substituted in ortho-, meta-, and para-positions of the phenyl ring is investigated using DFT and TDDFT with the range-separated hybrid CAM-B3LYP functional and the 6-311G(d,p) basis set. The solvent effects are taken into account within the polarized continuum model. The vibronic bandshape is simulated using a time-dependent linear coupling model with a vertical gradient approach through an original code. For flexible chromophores, the spectra of individual conformers are summed up with Boltzmann factors. It is shown that the long-wavelength absorption bandshape of DBMBF2 derivatives is determined by three factors: the relative statistical weights of conformers with different electronic absorption patterns, the relative position and intensity of the second low-energy electronic transition, and the vibronic structure of individual electronic peaks. The latter is governed by the relationship between the hard vibrational modes, which contribute to vibronic progression, and soft modes, which provide broadening of the peaks. The simulated spectra of the dyes in the study are generally consistent with the available experimental data and explain the observed spectral features.

Light‐Harvesting Nanotubes Formed by Supramolecular Assembly of Aromatic Oligophosphates

“…In ethanol, the oligomer is very soluble and the spectrum closely resembles that of the phenanthrene monomer (Supporting Information). [48][49][50][51][52][53] Phenanthrene aggregation leads to the disappearance of the 270 nm band and the occurrence of an H-band (243 nm). [48][49][50][51][52][53] Phenanthrene aggregation leads to the disappearance of the 270 nm band and the occurrence of an H-band (243 nm).…”

“…In amore polar,aqueous environment (see Figure 2f or experimental details), phenanthrenes exhibit strong aggregation behavior as revealed by asubstantial hypochromism, especially at 270 and 316 nm, and the characteristic changes in the vibronic structure. [48][49][50][51][52][53] Phenanthrene aggregation leads to the disappearance of the 270 nm band and the occurrence of an H-band (243 nm). [48,54] This suggests that oligomer 1 forms supramolecular polymers in which the phenanthrenes are arranged in extended Haggregates.H eating of the aqueous solution to 80 8 8Cl eads to disassembly of the polymers,w ith concomitant disappearance of the H-band.…”

Theoretical Study of the Intramolecular Localization and Migration of a Triplet Exciton in the N,N′-Di(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (α-NPD) Molecule

“…The normal modes responsible for the transition from one localized state to another (reorganization modes) were calculated according to the Lax model , utilizing the time-domain formalism and the multimode harmonic oscillator model. ,,, For the purposes of analysis and interpretation, the calculated spectra were deconvoluted into components corresponding to hard and soft modes according to the procedure developed in refs − . The hessians and gradients of the triplet states required in these calculations were calculated by CIS.…”

A new linear phenyloxazole–benzothiadiazole luminophore: crystal growth, structure and fluorescence properties

“…The vibronic absorption and emission spectra of BTD(PO) 2 (Fig. S6) were calculated according to the Lax model (Lax, 1952;Heller, 1981) utilizing the time-domain formalism and the multi-mode harmonic oscillator model (Yurenev et al, 2010;Kretov et al, 2012Kretov et al, , 2013Rukin et al, 2015).…”