Studying the Effect of the Environment on Quantum Tunneling Phenomena

• Grant number: 23/17013-0
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• Start date: April 08, 2024
• End date: April 07, 2025
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Nelson Henrique Morgon
• Grantee: Caio Moraes Porto
• Supervisor: Peter Richard Schreiner
• Host Institution: Instituto de Química (IQ). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil
• Institution abroad: Justus Liebig University Giessen (JLU), Germany
• Associated to the scholarship: 21/11039-1 - Development and Application of Analytical Approach for Calculating the Tunneling in Double-Well Potentials., BP.DR

Abstract

Quantum tunneling (QT) is the ability of particles and particle systems to traverse a region of higher energy. Such a process is characteristic of quantum systems and is prohibited by classical mechanics. Interest in QT has been revitalized in recent years due to increased computational power and new methods and strategies for its study. QT has been shown to be significant in a wide range of reactions, including combustion reactions, reactions involving proteins, sigmatropic rearrangements, elimination reactions, reactions with organometallics, carbenes, and nitrenes. Recently, a reaction that typically occurs predominantly due to tunneling was utilized for the production of intracellular reactive species for cancer treatment.The solvent effect in reactions involving quantum tunneling is not fully understood, and there are several open questions. Its comprehension is closely tied to the development of the field of tunneling catalysis, which is catalysis activated by QT, and to the understanding of tunneling as the third paradigm of reactivity. Various reactions have been demonstrated where QT is the decisive factor for the selectivity of a chemical system, as well as reactions that shouldn't occur due to insufficient total energy but nevertheless take place. In these cases, predicting the most probable product is impossible without analyzing the potential energy surface related to the reaction.The authors have developed a method for calculating quantum tunneling in symmetric and asymmetric double well potentials, demonstrating excellent agreement with experimental results and flexibility in modeling the studied systems. This project aims to utilize the tools developed and insights gained from published studies on the solvent effect on both reaction rates and QT, as well as on molecules embedded in cryogenic matrices, to shed light on its effect on quantum tunneling. Understanding the solvent effect on tunneling may pave the way for its effective utilization to adjust the selectivity of reactions that already occur via QT or that, due to this effect, will start occurring. Subsequently, the results of this study will be incorporated into the computational tool currently being developed for QT calculation by the authors.During the project period, it is intended to leverage the expertise of the foreign group to assist in refining the method developed, which is the focus of the student's research project. Among the points to be addressed are incorporating a variable reduced mass into the QT calculation method, which has been studied by the student and recently presented at a conference. The incorporation of multidimensional tunneling into the method is also being considered so that more complex systems can be treated with greater accuracy. Interactions between the studied molecules and the solvent will be initially explored through the analysis of non-covalent interactions. The solvent effects will be investigated employing implicit models (PCM, SMD) in combination with solvent molecules explicitly added through a hybrid solvation approach.