New parametrization scheme for the resonance integrals (H??) within the INDO/1 approximation. Main group elements

Neto, Joaquim Delphino Da Motta; Zerner, Michael C.

doi:10.1002/1097-461x(2001)81:3<187::aid-qua1>3.0.co;2-b

Cited by 29 publications

(14 citation statements)

References 91 publications

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“…The intermediate neglect of differential overlap for spectroscopy (INDO/S) technique of Zerner and coworkers 17, 18 was employed for the electronic spectra evaluation with the two‐electron integrals γ μν = (μμ|νν) calculated by a modified Mataga–Nishimoto recipe 26, 27. Two different parametrizations were employed: the original parametrization implemented by Pople et al 20, and the recent parametrization by Da Motta and Zerner 19, developed to obtain a unique set of parameters suitable both for geometric and for spectroscopic calculations.…”

Section: Experimental and Methodsmentioning

confidence: 99%

“…It can be observed that the calculated values reproduce very well the experimental ones, although better agreement was obtained with the Da Motta and Zerner's parametrization. This parametrization 19 was developed to be suitable for both geometric and spectroscopic calculations. In addition, SCRF calculations with the formulations suggested by Karelson and Zerner 30, 31 were carried out for a total of 21 different solvents; the results for their first electronic transition are presented in Table V.…”

Section: Indo/s+scrf Calculations For Planar Nrmentioning

confidence: 99%

“…The purpose of this paper is calculate the absorption spectra of NR with the semi‐empirical intermediate neglect of differential overlap for spectroscopy (INDO/S) method 17, 18 for both the twisted and nontwisted conformers. The new parametrization implemented by Da Motta and Zerner 19 was employed in addition to the original one implemented by Pople et al 20. Solvent effects were investigated by the self‐consistent reaction field (SCRF) continuous method and by the inclusion, at the input geometry, of some solvent molecules coordinated to the solute.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the Nile Red spectra by semi‐empirical calculations and spectrophotometric measurements

Dias

Custódio

Pessine

2006

Int J of Quantum Chemistry

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ABSTRACT:The spectroscopic behavior of Nile Red (NR) in solutions was investigated by spectrophotometric measurements and was calculated with the semiempirical intermediate neglect of differential overlap for spectroscopy (INDO/S) method. Two parametrizations implemented, respectively, by Pople and by Da Motta and Zerner, were employed; the solvent effects were simulated according to the dielectric continuum model [self-consistent reaction field (SCRF)], as well as with the explicit inclusion of solvent molecules. The calculations simulated reasonably well the experimental spectra and the intense solvatochromism of NR because the dipole moments were calculated to be higher in the first excited state than in the ground state. In addition, INDO/S calculations were carried out for partially optimized twisted conformers, whose electron donor moiety was orthogonal to the aromatic acceptor one and charge transfer was observed for excited states known as twisted intramolecular charge-transfer (TICT) states. In polar media, INDO/SϩSCRF calculations drastically stabilized the TICT state, reducing its energy down to the first excited state. Despite this intense solute-solvent stabilization, it is still less stable than the first excited state of the nontwisted, fully optimized conformer, and the limitations of the semi-empirical methods could not predict its role, if any, on the spectroscopic behavior of NR, except for the fact that the solvatochromism was explained independent of its presence.

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Section: Experimental and Methodsmentioning

confidence: 99%

Section: Indo/s+scrf Calculations For Planar Nrmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of the Nile Red spectra by semi‐empirical calculations and spectrophotometric measurements

Dias

Custódio

Pessine

2006

Int J of Quantum Chemistry

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“…This technique combines semiempirical Hamiltonians with a TDHF formalism, and makes computation of an excited state manifold not substantially more numerically demanding than ground state calculations. For CEO calculations we use Zerner's intermediate neglect of differential overlap/spectroscopy model [18][19][20] specifically parametrized to reproduce spectroscopic observables. Such CEO modeling has been successfully applied in the past to calculate optical properties of a variety of conjugated chromophores such as polymers ͑also with donors and acceptors͒, dendrimers, and biological light-harvesting complexes.…”

Section: A Quantum-chemical Calculationsmentioning

confidence: 99%

Exciton scattering approach for branched conjugated molecules and complexes. II. Extraction of the exciton scattering parameters from quantum-chemical calculations

Malinin

Tretiak

et al. 2008

The Journal of Chemical Physics

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We obtain the parameters of the exciton scattering (ES) model from the quantum-chemical calculations of the electronic excitations in simple phenylacetylene-based molecules. We determine the exciton dispersion and the frequency-dependent scattering matrices which describe scattering properties of the molecular ends as well as of meta- and orthoconjugated links. The extracted functions are smooth, which confirms the validity of the ES picture. We find a good agreement between the ES and quantum-chemical results for the excitation energies in simple test molecules.

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“… a The resonance integrals (β) were those of the exponential form suggested by Da Motta and Zerner 47, 48. The supermolecule includes four water molecules as shown in Figure 2. …”

Section: Resultsmentioning

confidence: 99%

Semiempirical INDO/S study on the solvatochromism of merocyanine dyes

Alencastro¹,

Neto

2001

Int J of Quantum Chemistry

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We report results of semiempirical intermediate neglect of differential overlap (INDO/S) calculations on the spectroscopy of 4 -hydroxy-1-methylstilbazolium betaine (HMSBB). Solvent effects were included using both the continuum and supermolecule approaches. The calculated spectra are compared with experimental ultraviolet-visible spectra for several solvents. The odd bathochromic shift of the low energy band (for nonpolar solvents) is tentatively discussed in terms of the contributions of different solvation mechanisms, and an assignment based on INDO/S calculated spectra is presented. We start from the assumption that in solution, conformations other than the completely planar structure (A) are possible. For protic solvents, in which hydrogen bonding constitutes the main contribution to solvation, calculations using the planar, fully optimized AM1 geometry reproduce fairly well the observed spectra. The intense, π → π * band is calculated close to 20,000 cm −1 , in good agreement with the experimental values in water and methanol. For the very polar formamide, the INDO/S+SCRF result is also very accurate, suggesting that formamide's strong polarity induces HMSBB to adopt the planar structure A. For polar solvents with nonspecific interactions such as acetonitrile or dimethylformamide, the situation is not as clear. We speculate that the experimental numbers can be reproduced only by a very large supermolecule. Finally, for nonpolar solvents such as cyclohexane, benzene and CCl 4 , the experimental number of 16,141 cm −1 (previously obtained from extrapolation of solvent mixtures by Jacques and coworkers) is reproduced by the INDO/S method only considering structures B and C. These results can be considered a confirmation of Jacques' suggestion that the solvatochromism of HMSBB can be explained by the solvents inducing a geometry change in HMSBB.

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New parametrization scheme for the resonance integrals (H??) within the INDO/1 approximation. Main group elements

Cited by 29 publications

References 91 publications

Investigation of the Nile Red spectra by semi‐empirical calculations and spectrophotometric measurements

Investigation of the Nile Red spectra by semi‐empirical calculations and spectrophotometric measurements

Exciton scattering approach for branched conjugated molecules and complexes. II. Extraction of the exciton scattering parameters from quantum-chemical calculations

Semiempirical INDO/S study on the solvatochromism of merocyanine dyes

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