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Developing a new class of molecular heaters to be applied in plants is a new strategy to extend locations suitable for agriculture to higher altitudes, preventing damages caused by the cold. The underlining idea is that molecular heaters are able to absorb UV-vis radiation and convert it into heat, in this case, to the leaves' surface. Inspired by nature and its efficient photoprotective features, we study derivatives of sinapoyl malate (SM). These derivatives exhibit a fast and efficient nonradiative decay. Their relaxation mechanisms involve a twist around their ethylenic-like double bond to generate a dark twisted charge transfer state, reaching a twisted conical intersection between S1/S0 states. These molecules were also investigated in a different medium to understand the effect of the environment in their photophysics. Another class of potential candidates as molecular heaters are the diketopyrrolopyrroles due to their photostability and strong visible light absorption. Moreover, it was recently shown that nonradiative pathways dominate the photophysics of some dimer derivatives. Here, we show that the dimer has a low-lying doubly excited state that is not energetically accessible to the monomer, and this delays the fluorescence allowing internal conversion to occur first. We characterize the doubly excited state wavefunction by systematically changing the derivatives to tune the \(\pi\)-scaffold size and the acceptor and donor characters. This analysis opens new ways to control the balance between luminescence and internal conversion in such systems. However, a proper characterization of doubly excited states is still a challenge, and no rigorous and transferable classification scheme between methods exists. Then, we propose classifying doubly excited states according to two limiting cases: the open- and closed-shell doubly excited states (DOS and DCS, respectively). We propose a classification scheme based on descriptors extracted from density matrices. As an example of DOS, we discuss formaldehyde dimer. On the other hand, DCS was more elusive. An investigation of butadiene and longer polyenes shows that none yields the idealized case. Additionally, we test the consistency of our classification scheme within ADC(3), MRCI and DFT/MRCI descriptions, in which most variation is due to the amount of static correlation.

International audience; In the Baeck-An (BA) approximation, first-order nonadiabatic coupling vectors are given in terms of adiabatic energy gaps and the second derivative of the gaps with respect to the coupling coordinate. In this paper, a time-dependent (TD) BA approximation is derived, where the couplings are computed from the energy gaps and their second timederivatives. TD-BA couplings can be directly used in fewest switches surface hopping, enabling nonadiabatic dynamics with any electronic structure methods able to provide excitation energies and energy gradients. Test results of surface hopping with TD-BA couplings for ethylene and fulvene show that the TD-BA approximation delivers a qualitatively correct picture of the dynamics and a semiquantitative agreement with reference data computed with exact couplings. Nevertheless, TD-BA does not perform well in situations conjugating strong couplings and small velocities. Considered the uncertainties in the method, TD-BA couplings could be a competitive approach for inexpensive, exploratory dynamics with a small trajectories ensemble. We also assessed the potential use of TD-BA couplings for surface hopping dynamics with time-dependent density functional theory (TDDFT), but the results are not encouraging due to singlet instabilities near the crossing seam with the ground state.

The photophysical behaviour of a given system can be strongly influenced by the presence of species in high concentrations due to possible excited state interactions, which may lead to the presence of new species in solution - called exciplexes (distinct molecules) or excimers (identical molecules). Since its discovery, species capable of forming exciplexes have been highlighted in important processes such as photodimerization, singlet fission and their use as biosensors. Exciplex formation can be understood based on two types of interaction: excitonic and charge resonances, which suggests a strong multi-referential character for such systems. However, describing the nature of these states is a challenge for medium to large systems due to their high computational cost, requiring the use of single-reference methods such as the time-dependent density functional theory (TD-DFT) and the algebraic diagrammatic construction scheme for the polarization propagator - ADC(2). A related challenge is the basis set choice. This work explores the effect of basis set and level of method on descriptors relevant for exciplex formation such as excitation energy, charge transfer index (CT), exciton average position, natural transition orbitals and the potential energy curves topologies along the ring spacing coordinate. To evaluate the influence of the number of aromatic rings on the exciplex formation, pyrene - naphthalene, pyrene - anthracene, pyrene - pyrene, pyrene - acylpyrene, acylpyrene - acylpyrene were studied. The results suggest that the cc-pVDZ and def2-SV (P) basis set exhibit similar qualitative descriptions in all studied systems. However, significant changes are observed among the tested methods, namely, TD-DFT with several functionals (PBE0, CAM-B3LYP, BHandHLYP and ωB97-XD) and RI-SOS-ADC(2) Regarding structural changes, the increase in the number of aromatic rings led to the increase of stability gain of these systems with the approximation between the fragments, accompanied by the increase of the CT, which is an indication that this parameter is associated with exciplex formation. Meanwhile, the introduction of a carbonyl group led to substantially different descriptions of the RI-SOS-ADC(2) and TD-DFT methods. It was possible to observe a relationship between the presence of possible crossings and differences in the topology of the exciplex potential energy curves with the charge transfer index behaviour along the same coordinates. This relation could be used qualitatively to understand the behaviour of the exciplexes. excited states of these systems. The functional PBE0 consistently disagrees with the description obtained by the other methods in the entire exciplex series studied, suggesting that this is not an appropriate method for these systems. Overall, the BHandHLYP and CAM-B3LYP functionalities show good agreement with each other, as do the TD-DFT / ωB97-XD and RI-SOS-ADC(2) levels. The choice of calculation level has proved to be a crucial step in the study of pyrene exciplexes and should be tested extensively.

Fil: Casal, Mariana Vanina. Univesidad de San Andrés. Escuela de Negocios; Argentina. Barrios, Marcelo

Fil: Casal, Mariana. Universidad de San Andrés. Escuela de Negocios; Argentina. Las personas están cada vez más conscientes de los problemas que ocasiona una mala alimentación, lo que las lleva a una constante búsqueda de opciones saludables. Las diversas necesidades de los consumidores son cubiertas por la gran variedad de productos que ofrece el mercado de bebidas. Dentro de este mercado existe un segmento que sobresale por su nivel nutrimental, y es precisamente AdeS la marca que ha impulsado y desarrollado esta categoría desde su lanzamiento. En este trabajo se desarrolla el plan de negocios del relanzamiento de AdeS, luego de haber sido adquirida por The Coca Cola Company en el año 2016. A través de diferentes herramientas se identificó el segmento objetivo y las necesidades, actualmente no satisfechas de nuestros clientes. La propuesta de valor se basa en brindar una opción saludable en bebidas, la cual aporte nutrición a la alimentación de las personas. e trata de un producto de consumo masivo, que pueda satisfacer las necesidades del rango etario de 20 a 50 años de un nivel socio económico alto/medio-alto. El proyecto requiere una inversión de U$s 229.418, y de acuerdo a los pronósticos y proyecciones económicas, el recupero de la inversión es de un año con una TIR de 116% y un VAN de U$s 2.211.072.

Fil: Ferrer Casal, Mariana. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.