Infrared induced chemical changes: Reaction mechanisms, electronic, energy and topological factors

• Grant number: 22/09269-1
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: March 01, 2023
• End date: February 28, 2026
• Field of knowledge: Physical Sciences and Mathematics - Chemistry - Physical-Chemistry
• Principal Investigator: Ataualpa Albert Carmo Braga
• Grantee: Leonardo José Duarte
• Host Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated scholarship(s): 23/13220-0 - Infrared-induced chemical reactions modelling, BE.EP.PD

Abstract

Recent studies on spectroscopy have demonstrated that infrared radiation can be used to induce conformational changes and breaking of chemical bonds in a precise and selective way, acting locally while the rest of the molecule remains undisturbed. When the infrared radiation interacts with a molecule, provoking a vibrational transition, the molecular energy rises and the system can overcome the potential barrier via tunneling effects, reaching another stable configuration. Although the first observation of such an effect was made in 1963, instrumental limitations at the time prevented the development of the technique, which was accomplished only in the last decade.In this project, we investigate this phenomena by means of state of art theoretical models in the dynamical study of electronic densities, including the Charge-Charge Transfer-Dipolar Polarization (CCTDP), that allows deep investigation of infrared intensities, the Interacting Quantum Atoms (IQA) energy decomposition scheme, that partitions the total energy of the system in terms of classical and exchange-correlation atomic contributions and the Relative Energy Gradient(REG) analysis method, identifying the most relevant energy components that control a dynamic chemical process. Preliminary results suggest that the combination of the above-mentioned methods composes a general picture from which one can extract information on how molecular vibrations of functional groups can affect all atoms in a molecule. The combination of IQA and REG methods also allows the determination of the reaction mechanism.

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DUARTE, LEONARDO J.; NUNES, CLAUDIO M.; FAUSTO, RUI; BRAGA, ATAUALPA A. C.. A protocol for the investigation of the intramolecular vibrational energy redistribution problem: the isomerization of nitrous acid as a case of study. Physical Chemistry Chemical Physics, v. 27, n. 7, p. 16-pg., 2025-01-22. (15/01491-3, 22/09269-1, 23/13220-0)

RICHTER, WAGNER EDUARDO; DUARTE, LEONARDO JOSE. IR intensities for out-of-plane vibrations at planar transition state structures: The NX3 series. VIBRATIONAL SPECTROSCOPY, v. 131, p. 7-pg., 2024-02-06. (22/09269-1)