2011 |
Mera-Adasme, R; Mendizabal, F; Olea-Azar, C; Miranda-Rojas, S; Fuentealba, P A Computationally Efficient and Reliable Bond Order Measure Artículo de revista Journal of Physical Chemistry A, 115 (17), pp. 4397-4405, 2011, ISSN: 1089-5639. Resumen | Enlaces | BibTeX | Etiquetas: auxiliary basis-sets, density, electron elements, exchange, localization, natural program resonance split-valence, superoxide-dismutase, theory, zinc @article{RN13, title = {A Computationally Efficient and Reliable Bond Order Measure}, author = { R. Mera-Adasme and F. Mendizabal and C. Olea-Azar and S. Miranda-Rojas and P. Fuentealba}, url = {/brokenurl#<Go to ISI>://WOS:000289824500031}, doi = {10.1021/jp107498h}, issn = {1089-5639}, year = {2011}, date = {2011-01-01}, journal = {Journal of Physical Chemistry A}, volume = {115}, number = {17}, pages = {4397-4405}, abstract = {Bond order indexes are useful measures that connect quantum mechanical results with chemical understanding. One of these measures, the natural bond order index, based on the natural resonance theory procedure and part of the natural bond orbital analysis tools, has been proved to yield reliable results for many systems. The procedure's computational requirements, nevertheless, scales so highly with the number of functions in the basis set and the delocalization of the system, that the calculation of this bond order is limited to small or medium size molecules. We present in this work a bond order index, the first order perturbation theory bond order (fopBO), which is based on and strongly connected to the natural bond orbital analysis tools. We present the methodology for the calculation of the fopBO index and a number of test calculations that shows that it is as reliable as the natural bond orbital index, with the same weak sensitivity to variations among commonly used basis sets and, as opposed to the natural bond order index, suitable for the study of large systems, such as most of those of biological interest.}, keywords = {auxiliary basis-sets, density, electron elements, exchange, localization, natural program resonance split-valence, superoxide-dismutase, theory, zinc}, pubstate = {published}, tppubtype = {article} } Bond order indexes are useful measures that connect quantum mechanical results with chemical understanding. One of these measures, the natural bond order index, based on the natural resonance theory procedure and part of the natural bond orbital analysis tools, has been proved to yield reliable results for many systems. The procedure's computational requirements, nevertheless, scales so highly with the number of functions in the basis set and the delocalization of the system, that the calculation of this bond order is limited to small or medium size molecules. We present in this work a bond order index, the first order perturbation theory bond order (fopBO), which is based on and strongly connected to the natural bond orbital analysis tools. We present the methodology for the calculation of the fopBO index and a number of test calculations that shows that it is as reliable as the natural bond orbital index, with the same weak sensitivity to variations among commonly used basis sets and, as opposed to the natural bond order index, suitable for the study of large systems, such as most of those of biological interest. |
Gajardo, F; Barrera, M; Vargas, R; Crivelli, I; Loeb, B Inorganic Chemistry, 50 (13), pp. 5910-5924, 2011, ISSN: 0020-1669. Resumen | Enlaces | BibTeX | Etiquetas: charge-transfer conversion, correlation-energy, density, excited-states, films, light, nanocrystalline optical-properties, sensitizers, tio2 @article{RN28i, title = {Influence of the Nature of the Absorption Band on the Potential Performance of High Molar Extinction Coefficient Ruthenium(Ii) Polypyridinic Complexes as Dyes for Sensitized Solar Cells}, author = { F. Gajardo and M. Barrera and R. Vargas and I. Crivelli and B. Loeb}, url = {/brokenurl#<Go to ISI>://WOS:000292010000012}, doi = {10.1021/ic1020862}, issn = {0020-1669}, year = {2011}, date = {2011-01-01}, journal = {Inorganic Chemistry}, volume = {50}, number = {13}, pages = {5910-5924}, abstract = {When tested in solar cells, ruthenium polypyridinic dyes with extended pi systems show an enhanced light-harvesting capacity that is not necessarily reflected by a high (collected electrons)/(absorbed photons) ratio. Provided that metal-to-ligand charge transfer bands, MLCT, are more effective, due to their directionality, than intraligand (IL) pi-pi* bands for the electron injection process in the solar cell, it seems important to explore and clarify the nature of the absorption bands present in these types of dyes. This article aims to elucidate if all the absorbed photons of these dyes are potentially useful in the generation of electric current. In other words, their potentiality as dyes must also be analyzed from the point of view of their contribution to the generation of excited states potentially useful for direct injection. Focusing on the assignment of the absorption bands and the nature of the emitting state, a systematic study for a series of ruthenium complexes with 4,4'-distyryl-2,2'-dipyridine (LH) and 4,4'-bis[p-(dimethylamino)-alpha-styryl]-2,2'-bipyridine (LNMe2) "chromophoric" ligands was undertaken. The observed experimental results were complemented with TDDFT calculations to elucidate the nature of the absorption bands, and a theoretical model was proposed to predict the available energy that could be injected from a singlet or a triplet excited state. For the series studied, the results indicate that the percentage of MLCT character to the anchored ligand for the lower energy absorption band follows the order [Ru(deebpy)(2)(LNMe2)](PF6)(2) > [Ru(deebpy)(2)(LH)] (PF6)(2) > [Ru(deebpy)(LH)(2)](PF6)(2), where deebpy is 4,4'-bis(ethoxycarbonyl)-2,2'-bipyridine, predicting that, at least from this point of view, their efficiency as dyes should follow the same trend.}, keywords = {charge-transfer conversion, correlation-energy, density, excited-states, films, light, nanocrystalline optical-properties, sensitizers, tio2}, pubstate = {published}, tppubtype = {article} } When tested in solar cells, ruthenium polypyridinic dyes with extended pi systems show an enhanced light-harvesting capacity that is not necessarily reflected by a high (collected electrons)/(absorbed photons) ratio. Provided that metal-to-ligand charge transfer bands, MLCT, are more effective, due to their directionality, than intraligand (IL) pi-pi* bands for the electron injection process in the solar cell, it seems important to explore and clarify the nature of the absorption bands present in these types of dyes. This article aims to elucidate if all the absorbed photons of these dyes are potentially useful in the generation of electric current. In other words, their potentiality as dyes must also be analyzed from the point of view of their contribution to the generation of excited states potentially useful for direct injection. Focusing on the assignment of the absorption bands and the nature of the emitting state, a systematic study for a series of ruthenium complexes with 4,4'-distyryl-2,2'-dipyridine (LH) and 4,4'-bis[p-(dimethylamino)-alpha-styryl]-2,2'-bipyridine (LNMe2) "chromophoric" ligands was undertaken. The observed experimental results were complemented with TDDFT calculations to elucidate the nature of the absorption bands, and a theoretical model was proposed to predict the available energy that could be injected from a singlet or a triplet excited state. For the series studied, the results indicate that the percentage of MLCT character to the anchored ligand for the lower energy absorption band follows the order [Ru(deebpy)(2)(LNMe2)](PF6)(2) > [Ru(deebpy)(2)(LH)] (PF6)(2) > [Ru(deebpy)(LH)(2)](PF6)(2), where deebpy is 4,4'-bis(ethoxycarbonyl)-2,2'-bipyridine, predicting that, at least from this point of view, their efficiency as dyes should follow the same trend. |
2011 |
A Computationally Efficient and Reliable Bond Order Measure Artículo de revista Journal of Physical Chemistry A, 115 (17), pp. 4397-4405, 2011, ISSN: 1089-5639. |
Inorganic Chemistry, 50 (13), pp. 5910-5924, 2011, ISSN: 0020-1669. |