Seeking a Direct Optimization Method Using Distance Geometry Space for Molecular Orientation

ABSTRACT We report a direct method to determine the relative configuration of two molecules using distance geometry, in which the structure is expressed as a set of distances between atoms. In the calculation, the gradient and bordered Hessian with inequality and equality constraints, based on the Cayley‐Menger determinant for embedding the structure in three‐dimensional space, are evaluated by introducing slack variables. The developed method is then applied to three molecular systems: O with , HF dimer, and with . The present approach could be related to a straightforward route to explore the entire potential‐energy landscape for a small molecular system described with simple analytical functions.