[en] During the past year the research under the contract has evolved along several lines consistent with the goal of achieving a better understanding of the interaction of molecules. First, was developed appropriate theoretical collision techniques and then implementation for practical systems of interest. This activity emphasized the determination of key physical factors controlling inelastic collision behavior. Also new methods were developed for inverting experimental relaxation data to yield detailed state-to-state rate constants. In addition a new effort was undertaken to develop efficient sensitivity analysis techniques for probing parameter dependencies in chemical kinetics systems. In summary, research on the following topics was pursued: physical analysis of atom-symmetric top collisions, vibration-rotation inelastic collisions in the CO-He System, collisional excitation of interstellar molecules: H₂, sensitivity analysis in quantum dynamics, correlation of relaxation data: application to (A¹Sigma/sub u/)Na₂*-Xe, vibrational-rotational relaxation from high vibrational state, in He-HD, the Green's function method of sensitivity analysis in chemical kinetics, and the classical path approximation in time-dependent quantum collision theory. The essence of these various activities is described in the body of this report. The publications resulting from this research contain further detailed information, and these papers are listed at the end of the report