Juan-Carlos Sancho-García

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Predicting accurate bond length alternations (BLAs) in long conjugated oligomers has been a significant challenge for electronic-structure methods for many decades, made particularly important by the close relationships between BLA and the rich optoelectronic properties of π-delocalized systems. Here, we test the accuracy of recently developed, and(More)
We have systematically analyzed the performance of some representative double-hybrid density functionals (including PBE0-DH, PBE-QIDH, PBE0-2, XYG3, XYGJ-OS, and xDH-PBE0) for a recently introduced database of diene isomerization energies. Double-hybrid models outperform their corresponding hybrid forms (for example, PBE0-DH, PBE0-2, and PBE-QIDH are more(More)
The difference between the length of the central carbon-carbon bond and that of the adjacent flanked double bonds in polymers such as polyacetylene is closely related to their electronic properties and plays a central role in their conductivity upon doping. Simple as it seems, this bond length alternation (BLA) is a difficult test for many theoretical(More)
We review why and how double-hybrid density functionals have become new leading actors in the field of computational chemistry, thanks to the combination of an unprecedented accuracy together with large robustness and reliability. Similar to their predecessors, the widely employed hybrid density functionals, they are rooted in the Adiabatic Connection(More)
The torsional profile of biphenyl has been calculated by means of quantum-chemical perturbations and coupled-cluster methods of increasing accuracy. The performance of the various theoretical approaches has been assessed through a critical comparison with experimental barrier heights. The theoretical data indicate that the basis set effects become more(More)
The non-covalent interactions in organic molecules are known to drive their self-assembly to form molecular crystals. We compare, in the case of anthracene and against experimental (electronic-only) sublimation energy, how modern quantum-chemical methods are able to calculate this cohesive energy taking into account all the interactions between occurring(More)
There have been tremendous efforts in the past decade on the use of computational methods for conjugated systems. Their properties and energetics are often described by density functional theory calculations which, however, are known to face a challenge when dealing with these systems since serious and systematic errors with popular density functionals(More)
By combining force-field approaches to quantum-chemical techniques, we have explored the influence of conformational changes on the nature of the lowest electronic excitations in model chains of poly(2-methoxy-5-(2'-ethylhexyl)oxy 1,4-phenylene vinylene) (MEH-PPV). The presence of conformational kinks yields a multichromophoric picture for the electronic(More)
The reliability of the Tao-Perdew-Staroverov-Scuseria (TPSS) exchange-correlation functional for the description of conjugation effects in model pi-conjugated systems has been thoroughly assessed through the calculation of torsion energy profiles. The functional reproduces qualitatively the shape of torsional potentials but, interestingly, the mixing of(More)
We assess here the reliability of orbital optimization for modern double-hybrid density functionals such as the parameter-free PBE-QIDH model. We select for that purpose a set of closed- and open-shell strongly and weakly bound systems, including some standard and widely used data sets, to show that orbital optimization improves the results with respect to(More)