Relation of molecular structure to Franck–Condon bands in the visible-light absorption spectra of symmetric cationic cyanine dyes

Lin, Katrina Tao Hua; Silzel, John W.

doi:10.1016/j.saa.2015.01.032

Cited by 17 publications

(19 citation statements)

References 64 publications

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“…Consequently many quantitative calculations concerning dyes which incorporated the effect of Duschinsky rotation were performed, whose modus operandi are consistent with the conclusion that “…the shoulders are not determined by a unique, dominant, vibrational normal mode but rather by a collection of singly excited vibrations.”…”

Section: Applicability Of the Franck–condon Principle To Polyatomic mentioning

confidence: 70%

“…Consequently many quantitative calculations concerning dyes which incorporated the effecto fD uschinsky rotation were performed, [37][38][39][40][41][42][43][44] whose modus operandi are consistent with the conclusion that "…the shoulders are not determined by au nique, dominant, vibrational normal mode but rather by ac ollection of singly excited vibrations." [35] In the following section we will discuss the "rightness"o f both models in light of spectroscopic data obtained from instrumental measurement.…”

Section: Applicability Of the Franck-condon Principle To Polyatomic Mmentioning

confidence: 70%

“…Because variations in vibrational frequency pertaining to this part of the chromophorei nduced by differences in groups at each end of the cyanine dyes tructure are relativelys mall, it mayb ed educed that the sub-bands arise from the coupling of av ibration of the polymethine chain with the S 0 -S 1 electronic transition.It is noteworthy that in Refs. [35,[37][38][39][40][41][42][43][44],P ouradier's work wasn either cited, nor was his analysis of experimental spectrad iscussed.…”

Section: Experimental Justification For the Franck-condon Intensity Dmentioning

confidence: 99%

“…Computational studies like that employed in 2007, which claim a proper theoretical analysis of the sub‐bands, continue to appear in the literature. Examples include papers dealing with the electronic spectra of cyanines, merocyanines and squaraines on the basis that the sub‐bands are composed of several peaks associated with different vibrations. As noted previously, this type of approach is far from one which relies on the role of a single dominant vibration in the electronic spectrum.…”

Section: Introductionmentioning

confidence: 99%

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Fine Structure in Electronic Spectra of Cyanine Dyes: Are Sub‐Bands Largely Determined by a Dominant Vibration or a Collection of Singly Excited Vibrations?

Mustroph

Towns²

2018

ChemPhysChem

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This work critically examines attempts to model the fine structure apparent in electronic spectra of cyanine dyes and their analogues. Numerous computational studies reported over the past decade attribute the origin of sub‐bands and their relative intensities to vibronic transitions in which the relevant electronic transition is coupled, irrespective of symmetry, with a collection of vibrations. It is contended that this type of approach is not supported by experimental evidence. An argument is reiterated for a more appropriate model that adheres closely to fundamental principles and fits the data. It stipulates that essentially just one symmetric vibration, carbon–carbon bond stretching of the cyanine polymethine chain, dominates the coupling and is responsible for the observed fine structure. Furthermore, it is pointed out that the intensities of the sub‐bands are readily explained by means of the Franck–Condon principle.

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Section: Applicability Of the Franck–condon Principle To Polyatomic mentioning

confidence: 70%

Section: Applicability Of the Franck-condon Principle To Polyatomic Mmentioning

confidence: 70%

Section: Experimental Justification For the Franck-condon Intensity Dmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Fine Structure in Electronic Spectra of Cyanine Dyes: Are Sub‐Bands Largely Determined by a Dominant Vibration or a Collection of Singly Excited Vibrations?

Mustroph

Towns²

2018

ChemPhysChem

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“…In computational chemistry there is a tendency to neglect the Franck–Condon principle and the Herzberg–Teller theory for strong, symmetry‐allowed electronic transitions . Based on the Herzberg–Teller theory within a symmetry‐allowed electronic transition in a polyatomic molecule, vibrations can appear as a progression only if the symmetry is the same in the excited state as in the ground state.…”

Section: Resultsmentioning

confidence: 99%

Bond length alternation in unsymmetrical cyanine dyes and its influence on the vibrational structure of their electronic absorption spectra

Mustroph

Reiner

Senns

2017

Coloration Technology

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Based on the assumption that the unsymmetrical cyanine dyes can be regarded as a hybrid of the two corresponding symmetrical dyes it was expected that λmax of the unsymmetrical dye would be the arithmetic mean of λmax of the two symmetrical dyes. There is, however, often a remarkable difference between the arithmetic mean and the observed λmax of the unsymmetrical dye – the Brooker deviation. To date, this effect is explained in terms of increasing electronic energy differences. With increasing difference of the electronic structure between the ground and excited state, the difference between equilibrium geometry of ground and excited state increases and the relative intensity of the higher vibronic transitions 0–v increases and that of the 0–0 transition decreases. λmax represents the intensity maximum of an absorption band and could be related to the 0–0, 0–1 or another vibronic transition. We discuss the origin of the Brooker deviation on the vibrational structure of the spectra.

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Role of Polymethinic Chain Substitution on the Two‐Photon Absorption Cross‐section of Heptamethine Cyanine Dyes

Guarin,

Mendoza‐Luna,

Galicia‐López

et al. 2023

ChemistrySelect

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The effect on the two‐photon absorption of heptamethine cyanines (HMCy) upon polymethinic chain substitution is explained via measurements with a femtosecond laser and time‐dependent/density functional theory calculations. An analysis of the optical properties of several HMCy is presented, emphasizing the similarities and differences between IR780 and HITC (used as a case study of HMCy), mainly by analyzing meso‐substitution and investigating the effect of intermediate structures between both molecules. The two‐photon absorption cross‐section of HITC diluted in methanol was measured, yielding a peak of 1838 GM at 830 nm. Spectroscopic and electronic structure computational data show that the change of polymethine chain substituents significantly affects excited state S4 of the molecules, modulating their transition moment and relative energy which, together with changes in the molecular geometry, govern non‐linear absorption.

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Relation of molecular structure to Franck–Condon bands in the visible-light absorption spectra of symmetric cationic cyanine dyes

Cited by 17 publications

References 64 publications

Fine Structure in Electronic Spectra of Cyanine Dyes: Are Sub‐Bands Largely Determined by a Dominant Vibration or a Collection of Singly Excited Vibrations?

Fine Structure in Electronic Spectra of Cyanine Dyes: Are Sub‐Bands Largely Determined by a Dominant Vibration or a Collection of Singly Excited Vibrations?

Bond length alternation in unsymmetrical cyanine dyes and its influence on the vibrational structure of their electronic absorption spectra

Role of Polymethinic Chain Substitution on the Two‐Photon Absorption Cross‐section of Heptamethine Cyanine Dyes

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