First Principles Determination of Reaction Rates

Carlo Cavallotti

Dipartimento di Chimica, Materiali e Ingegneria Chimica, “G. Natta”, Politecnico di Milano

Tuesday 27th November 2018

10:30:00

aula Saleri VI piano

The central focus of chemical kinetics is the determination of the rate at which one or more molecules react to transform into new molecules through the rearrangements of chemical bonds. Theoretically, chemical kinetics lies at the interface between quantum and classical mechanics, with the explicit formulation of rate laws requiring an extensive use of statistical thermodynamics. In the last years a priori rate calculations for gas phase reactions have undergone a gradual but dramatic transformation, with current predictions often rivaling the accuracy of the best available experimental data. In this seminar I will talk about the current status of ab initio chemical kinetics and of the challenges that must still be met in order to transform this branch of physical chemistry from a qualitative to a quantitative predictive science. A few example of research areas were contributions are necessary are the following: 1) the efficient determination of absolute and relative minima as well as first order saddle points on multidimensional potential energy surfaces for which gradient and, if necessary, Hessian information is available; 2) the determination of the number of energy states for a collection of non harmonic quantum oscillators; 3) the determination of a large number of eigenvalues for the quantum Hamiltonian of multidimensional rotors; 4) efficient approaches for the integration of the energy and momentum resolved master equation for chemically reactive systems.