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Quantum Chaos and Tunnelling in Chemical Reactions

Objective

The main aim of the project is to perform the study of quantum chaos and tunnelling in bimolecular chemical reactions by means of modern quantum and semi-classical approaches. Another important goal is the development parallel computer codes for modelling the quantum dynamics of chemical reactions.

We will construct a universal analytical model for the potential energy surface of a chemical reaction basing on analysis of topological, geometrical and analytical properties of the potential energy surfaces of different bimolecular chemical reactions. The model will have adjusting parameters and will be constructed in terms of generalized curvilinear coordinates. Using the Levenberg-Markar algorithm we will develop a program for the calculation of an optimal parameter set, which will allow the model to approximate the ab-initio potential energy surface of a chosen chemical reaction as closely as possible. The surface fitted in this way will be compared to the surfaces fitted to the ab-initio data using other, more conventional methods, such as spline interpolation and the reproducing kernel Hilbert space method.

We will compare different modern methods of performing reactive scattering calculations for the simple bimolecular chemical reactions H + H2 -> H2 + H and H + D2 -> HD + D. The methods to be investigated will be: the time-dependent wave packet method, the Faddeev equations method and the micro-irreversible quantum approach. The tunnelling transitions, the transition state dynamics, the quantum chaos phenomenon and its relation with the reaction surface geometry will be investigated in detail. We will also explore the sensitivity of these phenomena to small deformations of the potential energy surface especially in the region of the transition state geometry.

We plan to investigate the role of quantum chaos in tunnelling. This will improve our understanding of the correspondence between the classical dynamical systems and their quantum analogues in semi-classical limit, which is a fundamental problem in modern quantum mechanics.

The hydrogen exchange reactions of type OH + OH -> H2O + O, Cl + CH4 -> HCl + CH3 and O + CH4 -> OH + CH3 will be investigated in detail. The quantum calculations of transition probabilities will be performed by means of both time-dependent wave packet and micro-irreversible quantum representation methods.

The quantum chaos phenomenon and reaction complex formation will be investigated in detail. It is planned to compute the rate constants for the reactions OH + OH -> H2O + O and Cl + CH4 -> HCl + CH3 using time-dependent quantum mechanical and micro-irreversibly quantum approaches.

Parallel computer codes for calculating rate constants for bimolecular chemical reactions will be written and implemented on the massive parallel computers Parsytec CC/16 and SPP-1600 (IHPCDB, St. Petersburg, Russia) and on ArmCluster (WDC/64 IIAP, NAS Yerevan, Armenia).

Coordinator

University of Bristol
Address
Cantock's Close 1
BS8 1TS Bristol
United Kingdom

Participants (4)

Göteborg University
Sweden
Address
412 96 Göteborg
412 96 Göteborg
Institute for High Performance Computing and Information Systems
Russia
Address
Fontanka Emb. 6
191187 St. Petersburg
Institute for Informatics and Automation Problems
Armenia
Address
Parujr Sevak 1
375014 Yerevan
Saint Petersburg State University
Russia
Address
Ulyanovskaya 1
198504 Saint Petersburg