Theoretical Studies of Electronically Adiabatic and Non-Adiabatic Chemical Reaction Dynamics

Author: Bowman, Joel Mark

Year: 1975

Degree: Dissertation (Ph.D.)

Advisor: Kuppermann, Aron

Committee Member: Unknown, Unknown

Option: Chemistry

DOI: 10.7907/6F8N-ZE84

Abstract

Part I presents several sets of comparisons of semi-classical, quasi-classical and exact quantum reactive scattering calculations for collinear chemical reactions. The possibility of modifying the standard quasi-classical method according to a quantum criterion is investigated. The systems studied are H + H_2, F + H_2, and F + D_2. In addition, a theoretical investigation of the semi-classical S matrix is made.

Details of a quasi-classical current density analysis of the H + H_2 reaction are presented and a comparison with exact quantum results is made.

A direct test of two versions of the vibrationally adiabatic theory of chemical reactions is made in Part II for the H + H_2 reaction. The adiabaticity of the symmetric stretch motion of the H_3 transition state is focussed upon. In addition, a determination of the completeness of adiabatic basis sets for scattering calculations is made.

The theory of electronically non-adiabatic chemical reactions is presented in Part III. Quantum calculations of the collinear H^+ + H_2 → H_2 + H^+ reaction are described. A model and a realistic potential energy surface are employed in these calculations.

A fictitious electronically non-adiabatic H + H_2 collinear chemical reaction is treated quantum mechanically. Two potential energy surfaces and a coupling surface are developed for this purpose.

The reaction Ba(^1S) + ON_2(X^1Σ) → BaO(X^1Σ) + N_2(X^1Σ^+_g), BaO(a^3II) + N_2(X^1Σ^+_g) is studied quantum mechanically. The singlet and triplet potential energy surfaces are devised as is a spin-orbit coupling surface. Electronically adiabatic and non-adiabatic transition probabilities are calculated as a function of the initial translational energy of the reagents.

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