Exploration and elaboration of photo-induced proton transfer dynamical mechanism for novel 2-[1,3]dithian-2-yl-6-(7aH-indol-2-yl)-phenol sensor

In this work, we theoretically probe into the photo-induced hydrogen bonding effects between S0 state and S1 state as well as the excited state intramolecular proton transfer(ESIPT) behavior for a novel 2-[1,3]dithian-2-yl-6-(7aH-indol-2-yl)-phenol(DIP) probe system. We first study the ground-state hydrogen bonding O–H··· N behavior for DIP. Then we analyze the primary geometrical parameters(i.e., bond length, bond angle, and infrared(IR) stretching vibrational mode)involved in hydrogen bond, and confirm that the O–H··· N of DIP should be strengthened in the first excited state. It is the significant prerequisite for ESIPT reaction. Combining the frontier molecular orbitals(MOs) with vertical excitation analyses, the intramolecular charge transfer(ICT) phenomenon can be found for the DIP system, which reveals that the charge redistribution facilitates ESIPT behavior. By constructing potential energy curves for DIP along the ESIPT reactional orientation, we obtain quite a small energy barrier(3.33 kcal/mol) and affirmed that the DIP molecule undergoes ultrafast ESIPT process once it is excited to the S1 state and quickly transfers its proton, forming DIP-keto tautomer. That is why no fluorescence of DIP can be observed in experiment, which further reveals the ultrafast ESIPT mechanism proposed in this work.

Unmanned Aerial Vehicle Formation Inspired by Bird Flocking and Foraging Behavior

This paper considers a multiple unmanned aerial vehicles （UAV） formation problem and proposes a new method inspired by bird flocking and foraging behavior. A bidirectional communication network, a navigator based on bird foraging behavior, a controller based on bird interaction and a movement switch are developed for multi-UAV formation. Lyapunov＇s second method and mechanical energy method are adopted for stability analysis. Parameters of the controller are optimized by Levy-flight based pigeon inspired optimization （Levy-PIO）. Patrol missions along a square and an S shaped trajectory are designed to test this formation method. Simula- tions prove that the bird flocking and foraging strategy can accomplish the mission and obtain satisfying performance.