Chromophores density functional theory

The following sections are purposely separated into specific structural classes of square planar Pt" complexes of the general formulae Pt(NAN)(C=CR)2, [Pt(NANAN) (OCR)]+, Pt(NANAC)(C=CR), rra s-Pt(PR3)2(OCR)2, and d.v-Pt(PAP)(( =CR)2, where NAN is a bidentate 2,2 -bipyridine, NANAN and NANAC are tridentate polypyridines, PR3 is a monodentate phosphine, and PAP is a bidentate phosphine ligand. The final section of this work is dedicated to recent electronic structure calculations on these molecules with an emphasis on the successful application of DFT (density functional theory) and TD-DFT (time-dependent density functional theory) methods towards understanding the absorption and emission processes of these chromophores. 

Density functional theory (DFT) calculations of two types of push-pull chromophores built around thiophene-based 7t-conjugating spacers rigidified by either covalent bonds or noncovalent intramolecular interactions (Figure 6) have been carried out to assign the relevant electronic and vibrational features and to derive useful information about the molecular structure of these NLO-phores <2003CEJ3670>. 

Kobko, N., Masunov, A., Trehak, S. CalculaUons of the third-order nonUnear optical responses in push-pull chromophores with a hme-dependent density functional theory. Chem. Phys. Lett. 392, 444 51 (2004)... 

Masunov, A., Tretiak, S. Prediction of two-photon absorption properties for organic chromophores using time-dependent density-functional theory. J. Phys. Chem. B 108, 899-907 (2004)... 

Deriving a force field for chromophores entails calculations of the electronic structure of these large molecules. In recent times, the density functional theory (DFT)[15j approach has been gaining popularity in the... 

Rose Ml, Mascharak PK (2009) Photosensitization of Ruthenium nitrosyls to red light with an isoelectronic series of heavy-atom chromophores experimental and density functional theory studies on the effects of 0-, S- and Se-substituted coordinated dyes. Inorg Chem 48 6904-6917... 

Mennucd B, Cappelli C, Guido CA, Cammi R, Tomasi J. Stmctures and properties of electronically excited chromophores in solution from the polarizable continuum model coupled to the time-dependent density functional theory.JPhys Chem A. 2009 113(13) 3009-3020. http //dx.doi.org/10.1021/jp8094853. 

Photon Absorption Properties for Organic Chromophores Using Time-Dependent Density-Functional Theory. 

The chromophore has been treated at the Hartree-Fock or density functional theory level (see Chapter 4), in the determination of both its ground state and its properties. This model for the molecule represents a remarkable progress in the accuracy of the description of the molecular chromophore compared to polarizable point dipole model. The solvation effects have been described with the PCM. More in details, the solvent is described as a continuum dielectric which occupies all the space free from the metal specimen and the molecule is hosted in a molecular shaped cavity inside such dielectric. 

The absorption of far-IR photons can be detected by the messenger method, which is based on forced evaporation of a weakly-bound ligand from the cluster complex upon the absorption of a small number of IR photons. The messenger method assumes that only the metal cluster acts as a chromophore while the detached atomic or molecular ligand merely delivers the message about the absorption event without perturbing the structural properties of the cluster. This assumption is fulfilled for most transition metal clusters complexed with rare gas atoms. In combination with density functional theory calculations, the experimental IR (multi) photon dissociation, IR-(M)PD, spectra often enable an unambiguous determination of the clusters structure. 

Recently, an extensive study on the photoexcitation and isomerization of PYP was published. In this study, a combination of molecular dynamics simulation techniques and time-dependent density functional theory calculations were used. Several interesting results were obtained. Out of five separate simulations that were performed of the excited state, two showed a twisted configuration of the chromophore, and in three, the chromophore retained its trans configuration. This could explain the two different excited states observed in the ultrafast absorption measurement (see above). 

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