Reaction-Path Dynamics in Redundant Internal Coordinates

This paper presents a general method for reaction-path calculations with redundant curvilinear internal coordinates. Following Pulay and Fogarasi, the generalized inverse of the Wilson 𝒢 matrix is used to remove the redundancy of the curvilinear internal coordinates. An illustrative application to HBr + HCCH → H2CCHBr is presented, and the results with the new algorithm are compared to calculations with rectilinear coordinates.