Evaluating models of reaction dynamics

The Valentini group has previously put forth two distinct reaction models that identify key aspects controlling the dynamics of bimolecular reactions. In this thesis, the generality and accuracy of each of these models is evaluated.; A "local" reaction model has been developed to explain trends in rotational energy disposal of atom + polyatom reaction as a function of the structure of the polyatomic reactant. The model identifies two aspects of reactant structure as key in determining the dynamics of the reaction. These are the rotational constants of the structured co-product and the opacity function to abstraction at each potential abstraction site as defined by a local impact parameter. The local model provides a good description of the rotational energy disposal in the series of reactions H + RH → H2 + R (R = linear and cyclic alkanes up to 6 carbons) through which the model was developed. Here, the set of applicable measurements is extended to two series of reactions, H + HCnF2n+1 → H2 + CnF 2n+1 (n = 2,3) and H + HR → H2 + R (R = i-C4H 10, C(CH3)4), for which the local model makes disparate predictions of rotational energy disposal. The rotational state distributions of the H2(v') product at 1.6 eV collision energy were measured. Those results were compared to the series of linear and cyclic alkanes previously studied using a linear surprisal analysis. The local model was found to correctly explain the observed trends in rotational energy disposal in all but one vibrational state of one of the studied reactions.; Separately, a simple function of kinematics has been put forth to explain an observed bias against internal energy in the products of suprathreshold energy reactions. A model based on constraints on the atomic motion in such reactions across a generalized potential surface has been developed to derive the form of that function. Quasiclassical trajectory calculations were run on the H + HCl → H2 + Cl system and its isotopic variants D + HCl → HD + Cl, and H + DCl → HD + Cl to determine whether individual trajectories behave in the manner described by the kinematic model. It is found that while the model correctly predicts that highest allowed product internal energy state across a wide range of reactions, the model incorrectly describes a constraint on the behavior of individual trajectories. This is attributed to unanticipated behavior of the potential energy surface at highly non-collinear geometries.; Finally, these two models are used to identify unique dynamics in the H-by-H abstraction from cyclopropane. The H2 product is found to be too energetic to have resulted from direct abstraction, and a surprising channeling of the ring opening energy in the system into that H2 product is suggested.