Ab Initio studies of the excited state polarizabilities of Ozone and Thiozone

We report an Ab Initio CIS (D) study of the electric dipole polarizability and first hyperpolarizability for the ground and five lowest electronic excited singlet states of ozone and thiozone. Optimized molecular geometries and the electric dipole moment are also given for each state. Ground state properties were also calculated using the B3LYP model. We give results for the less stable D3h ring structures. Energy gaps between the C2v and D3h structures were also estimated by the HF, CISD, G3, B3LYP and G3B3 models. The D3h structure is less polarizable than the C2v ground state for both species. Our results reveal substantial differences between the electronic properties from excited state to excited state

Enhancement of molecular polarizabilities by the push-pull mechanism; a DFT study of substituted benzene, furan, thiophene and related molecules

We report Density Functional Theory (DFT) studies of the dipole polarizabilities of benzene, furan and thiophene together with a number of substituted and related systems. All geometries were optimized (and characterized) at the B3LYP/6-311g (2d, 1p) level of theory and polarizabilities then calculated with B3LYP/6-311++ G (2d, 1p). For the R-ring systems we find group polarizabilities in the order R= NO2∼ OCH3∼ CN∼ CHO> NH2> OH> H= 0. For systems R-ring-R, differs little from the additivity model, with small positive and negative increments. For systems D-ring-A (where D and A are deactivating and activating groups) we find a positive enhancement to over and above the value expected on the basis of pure additivity for all pairs A and D studied. This enhancement can be increased greatly by extending the length of the conjugated chain to D-ring-CH= CH-ring-A and D-ring-N= N-ring-A systems

Propiedades ópticas no lineales del difosfaferroceno. Un estudio teórico

Non linear optics (NLO) has been developed in recent years as an important field of research due to its applicability in photoelectronics and photonic technology. In recent decades organometallic complexes have become a class of molecules of great interest in NLO. These complexes combine the advantages of organic molecules with the ones offered by inorganic salts. In this work, a computational quantum mechanics study of the electronic contribution in gas phase of the optical properties of diphosphaferrocene at a static level was carried out, using the CAM-B3LYP DFT Method and the 6-31+G(d,p) basic set, together with the finite field methodology based on Kurtz equations. Additionally, the ferrocene molecule was studied for comparison purposes. The theory-experimental comparison shows that the methodology used provides comparable values, showing a 93% correspondence for aave, and 87% for gave. With respect to the optical properties, it is observed that the diphosphaferrocene complex is mostly more polarizable than ferrocene. However, the greatest contributions are observed in the NLO properties, where for b, the calculated response for the diphosphaferrocene complex is 72 ua, different from, which does not respond because it is a symmetric center molecule. In gave, the answer is almost double. These results allow us to infer that the interaction of phospholyl rings with the Fe atom causes a greater perturbation or delocalization of the electronic density of the molecule, promoting high optical responses when an electric field is applied, cataloging it as a potential candidate for the design of new NLO materials.   Key words: NLO, diphosphaferrocene, optics, DFT, (hyper) polarizabilities.  La óptica no lineal (NLO, por sus siglas en inglés de: No Linear Optics) se ha desarrollado en los últimos años como un importante campo de investigación debido a su aplicabilidad en la fotoelectrónica y tecnología fotónica. En las últimas décadas los complejos organometálicos se han convertido en una clase de moléculas de gran interés en NLO. Estos complejos combinan las ventajas de las moléculas orgánicas con las ofrecidas por las sales inorgánicas. En este trabajo se realizó un estudio mecano-cuántico computacional de la contribución electrónica en fase gas de las propiedades ópticas del difosfaferroceno a nivel estático, empleando el método DFT CAM-B3LYP y el conjunto base 6-31+G(d,p), en conjunto con la metodología de campo finito basadas en la ecuaciones de Kurtz. Adicionalmente se realizaron cálculos para el ferroceno a modo comparativo. La comparación teoría-experimentales, muestra que la metodología empleada proporciona valores comparables, mostrando una correspondencia de 93 % para aave, y un 87 % para gave. Con respecto a las propiedades ópticas, se observa que el complejo de difosfaferroceno es mayormente polarizable que el ferroceno. Sin embargo, las mayores contribuciones se observan en las propiedades NLO, donde para b la respuesta calculada para el complejo difosfaferroceno es 72 ua, a diferencia de ferroceno el cual no presenta respuesta por ser una molécula centro simétrica. En gave, la respuesta es casi dos veces superior. Estos resultados permiten inferir que la interacción de anillos fosfolil con el átomo de Fe origina una mayor perturbación o deslocalización de la densidad electrónica de la molécula, promoviendo así elevadas respuestas ópticas cuando se aplican campos eléctricos, catalogándolo como un candidato potencial para el diseño de nuevos materiales NLO.   Palabras clave: NLO, difosfaferroceno, óptica, DFT, (hiper)polarizabilidades.   Abstract Non linear optics (NLO) has been developed in recent years as an important field of research due to its applicability in photoelectronics and photonic technology. In recent decades organometallic complexes have become a class of molecules of great interest in NLO. These complexes combine the advantages of organic molecules with the ones offered by inorganic salts. In this work, a computational quantum mechanics study of the electronic contribution in gas phase of the optical properties of diphosphaferrocene at a static level was carried out, using the CAM-B3LYP DFT Method and the 6-31+G(d,p) basic set, together with the finite field methodology based on Kurtz equations. Additionally, the ferrocene molecule was studied for comparison purposes. The theory-experimental comparison shows that the methodology used provides comparable values, showing a 93% correspondence for aave, and 87% for gave. With respect to the optical properties, it is observed that the diphosphaferrocene complex is mostly more polarizable than ferrocene. However, the greatest contributions are observed in the NLO properties, where for b, the calculated response for the diphosphaferrocene complex is 72 ua, different from, which does not respond because it is a symmetric center molecule. In gave, the answer is almost double. These results allow us to infer that the interaction of phospholyl rings with the Fe atom causes a greater perturbation or delocalization of the electronic density of the molecule, promoting high optical responses when an electric field is applied, cataloging it as a potential candidate for the design of new NLO materials.   Key words: NLO, diphosphaferrocene, optics, DFT, (hyper) polarizabilities

Synthesis and Luminescence Modulation of Pyrazine-Based Gold(III) Pincer Complexes

The first examples of pyrazine-based gold(III) pincer complexes have been synthesized; their intense photoemissions can be modified by interactions with the non-coordinating pyrazine-N atom. Luminescence modulation is possible without the need for altering the ligand framework. Emissions shift from red (77 K) to blue (298 K) due to thermally activated delayed fluorescence (TADF

Density functional and CIS (D) studies on the ground and excited electronic state properties of nitrogen dioxide

We report Ab Initio and DFT calculations for the ground and the lowest five electronic excited states of nitrogen dioxide. Molecular geometries, together with the electric dipole moment, molecular dipole polarizability and first hyperpolarizability are given for each state. We fitted the ground state ( [TeX:]^ 2A_1) mean polarizability and anisotropy to a fourth order Taylor series expansion to account for the effect of the symmetric stretch. The first five excited states were treated using the UCIS and UCIS (D) models; these models give a poor representation of the excited state energies, but demonstrate the substantial differences between the molecular electronic properties for the six electronic states considered

On the electronic excited states of sulfur dioxide

We report Ab Initio calculations for the ground and lowest electronic excited states of sulfur dioxide. Molecular geometries, together with the electric dipole moment, dipole polarizability and first hyperpolarizability are given for each state. Ground state properties were calculated using the HF and B3LYP models, whilst excited states were modelled using CIS and CIS(D). Our results reveal substantial differences between these properties