Preparation of vibrational quasi-bound states of the transition state complex BrHBr from the bihalide ion BrHBr.

Efficient strategies that allow the preparation of molecular systems in particular vibrational states are important in the application of quantum control schemes to chemical reactions. In this paper, we propose the preparation of quasi-bound vibrational states of the collinear transition state complex BrHBr, from vibrational states of the bihalide ion BrHBr-, that favor the bond selective breakage of BrHBr. The results shown complement the investigation that we reported in a previous paper, [A. J. Garzón-Ramírez, J. G. López and C. A. Arango, Int. J. Quantum Chem., 2018, 24, e25784], in which we demonstrated the feasibility of controlling the bond selective decomposition of the collinear BrHBr using linear combinations of reactive resonances. We employed a dipole moment surface, calculated at the QCISD/d-aug-cc-pVTZ level of theory, to simulate the interaction of the BrHBr- ground vibrational state with heuristically optimized sequences of ultrashort infrared linear chirped laser pulses to achieve a target vibrational state, resulting from expanding a chosen linear combination of reactive resonances of BrHBr in terms of vibrational eigenstates of BrHBr-. The results of our simulations show final states that capture the most relevant features of the target state with different levels of description depending on the sequence of laser pulses employed. We also discuss ways of improving the description of the target state and possible limitations of our approach.

Guía atrapada durante cambio de electrodo del seno coronario en terapia de resincronización cardiaca / Trapped guidewire during coronary sinus electrode exchange in cardiac resynchronization therapy

Resumen Se presenta el caso de una paciente con atrapamiento de guía al interior del seno coronario durante el procedimiento de cambio de un electrodo (Sentus ProMRI OTW BP L-85) por desalojo asociado a disfunción de la terapia de resincronización cardiaca. Durante el implante del nuevo electrodo se presentó atrapamiento y retención intravascular de la guía utilizada para su posicionamiento a nivel del seno coronario, lo cual hizo imposible su remoción. La paciente no aceptó tratamiento quirúrgico, se encuentra en vigilancia médica y permanece asintomática desde hace 3 años.

Abstract It is reported the case of a patient with guidewire trapping inside the coronary sinus during an electrode exchange procedure (Sentus ProMRI OTW BP L-85) due to dislocation associated with dysfunction of cardiac re-synchronization therapy. During the implantation of the new electrode, entrapment of the guidewire used for its positioning at the level of the coronary sinus and intravascular retention were presented, making it impossible to remove it. The patient did not accept surgical treatment and has been under medical surveillance, asymptomatic for three years.

Validation by Molecular Dynamics of the Major Components of Sugarcane Vinasse, On a Surface of Calcium Carbonate (Calcite).

There is ongoing interest in the alcohol industry to significantly reduce and/or add value to the liquid residue, vinasse, produced after the distillation and rectification of ethanol from sugar cane. Vinasse contains potassium, glycerol, and a protein component that can cause environmental issues if improperly disposed of. Currently, some industries have optimized their processes to reduce waste, and a significant proportion of vinasse is being considered for use as an additive in other industrial processes. In the manufacture of cement and asphalt, vinasse has been used in the mixtures at low concentrations, albeit with some physical and mechanical problems. This work is the first molecular approximation of the components of the sugar cane vinasse in an industrial context, and it provides atomic details of complex molecular events. In the current study, the major components of sugar cane vinasse, alone or complexed on the surface of calcium carbonate, were modeled and simulated using molecular dynamics. The results showed that the protein component, represented by the mannoprotein Mp1p, has a high affinity for forming hydrogen bonds with potassium and glycerol in the vinasse. Additionally, it provides atomic stability to the calcium carbonate surface, preserving the calcite crystalline structure in the same way potassium ions interact with the carbonate group through ion-dipole interactions to improve the cohesion of the modeled surface. On the contrary, when the glycerol molecule interacts with calcium carbonate using more than two hydrogen bonds, it triggers the breakdown of the crystalline structure of calcite expanding the ionic pair.

Analytical optimal pulse shapes obtained with the aid of genetic algorithms.

We propose a methodology to design optimal pulses for achieving quantum optimal control on molecular systems. Our approach constrains pulse shapes to linear combinations of a fixed number of experimentally relevant pulse functions. Quantum optimal control is obtained by maximizing a multi-target fitness function using genetic algorithms. As a first application of the methodology, we generated an optimal pulse that successfully maximized the yield on a selected dissociation channel of a diatomic molecule. Our pulse is obtained as a linear combination of linearly chirped pulse functions. Data recorded along the evolution of the genetic algorithm contained important information regarding the interplay between radiative and diabatic processes. We performed a principal component analysis on these data to retrieve the most relevant processes along the optimal path. Our proposed methodology could be useful for performing quantum optimal control on more complex systems by employing a wider variety of pulse shape functions.

Communication: One-photon phase control of cis-trans isomerization in retinal.

We computationally demonstrate the one-photon phase control of retinal isomerization under conditions of low laser intensity. The calculations, utilizing the multiconfigurational time dependent Hartree method, include coupling between the two modes that are active in isomerization and the background molecular vibrational environment. Noting previously unsuccessful computations highlights the significance of this result.