The Quantum Dynamics of Atom Plus Diatom Chemical Reactions

Citation

Schatz, George Chappell (1976) The Quantum Dynamics of Atom Plus Diatom Chemical Reactions. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/2N85-G728. https://resolver.caltech.edu/CaltechETD:etd-09012006-080950

Abstract

The results of accurate quantum dynamical calculations on one, two and three dimensional atom plus diatomic molecule electronically adiabatic chemical reactions are presented.

In papers 1 and 2, comparisons between quantum, quasi-classical and semi-classical results for the collinear F + H₂ and F + D₂ reactions, are examined. Paper 3 discusses the role of reactive and nonreactive collisions in producing vibrational deactivation in the collinear H + FH, D + FD, H + FD and D + FH systems.

The extension of reactive scattering calculational methods to atom diatom collisions on a plane and in three dimensions is presented in papers 4 and 6, respectively. In both applications, the Schrodinger equation is solved by a coupled equation method in each of the three equation arrangement channel regions. This is followed by a matching procedure in which the wave function is made smooth and continuous at the boundaries of these regions, In the three dimensional case, the use of body fixed coordinates is crucial to obtaining an efficient coordinate transformation between arrangement channels.

Applications of these 2D and 3D methods to the H + H₂ exchange reaction are presented in papers 5 and 7. Integral and differential cross sections, reaction probabilities, product and reagent state rotational distributions, and other dynamical information are discussed in the papers, and these results are extensively compared with those of previous quasi-classical, semi-classical and approximate quantum calculations. The results of a very simple angular momentum decoupling approximation are considered in paper 7.

In papers 8 and 9 the relative importance of direct versus resonant (shape or Feshbach) mechanisms for several atom diatom reactions is examined. A number of techniques for characterizing both mechanisms are discussed, including time delays, eigenphase shifts, Argand diagrams and the collision lifetime matrix. Extension of these 1D resonances to the 2D and 3D reactions is examined in paper 10 for the simple case of H + H₂.

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