Nonlinear optical (NLO) properties allow the engineering of a variety of optical devices like organic light-emitting diodes, field effect transistors, and optical sensors, being promissory in fields like telecommunications and electronic engineering, for instance. In opposition to common inorganic chromophores, organic dyes are advantageous once they better resist the breakdown stresses caused by high-power lasers, besides functionalizing diverse circuits with pronounced packaging and miniaturization capabilities. Due to these potentialities, we have experienced a great discussion about how to tune and improve the NLO of organic chromophores. In this direction, besides usual chemical synthesis, proton scavenging procedures can modulate the ONL response of some dyes over a wide range of values. Considering all aspects presented above and attempting to understand these effects, we discuss how the association of solute-solvent interactions and proton remotion can affect two popular dyes, methyl orange, and p-coumaric acid.

Positrons and positronium (Ps) atoms are important nanoscale probes in materials sciences useful to investigate materials properties. Positronic interactions in liquid phase are specially important for a well established imaging technique, Positron Emission Tomography (PET), which explores the signatures of gamma radiation produced by pair annihilation from positron-electron. In this context, we will present our recent results about positronic interactions with hydrated biomolecules and discuss the existence of such positronic compounds in water. Apart from positronic interactions with biomolecules, we will also discuss recent improvements in our model to simulate the solvated positronium in water.

High resolution X-ray spectroscopy is a powerful tool to probe properties of materials. Resonant scattering processes such as resonant inelastic X-ray scattering (RIXS) are techniques that allow one to characterize electronic and vibrational structures of molecules in both gas and liquid phases. In this seminar I present the theoretical approaches used to model RIXS spectroscopy in recent applications. Particularly, it will be discussed how the concept of detuning can be explored to control the quantum nuclear dynamics of excited states.

gravação do seminário: portal.if.usp.br/gfmm/sites/portal.if.usp.br.ifusp/files/Seminario-GFMM-KalineCoutinho-19Fev21.mp4