Removing chemical bonding ambiguities in condensed media by steepest-descent quenching.

Chemical bonds between neighboring pairs of atoms tend to be significantly shorter than distances between non-bonded pairs that are in "van der Waals" contact. Consequently there is usually no theoretical uncertainty in identifying chemical bonds in cold dense media from the atomic pair correlation functions: covalently bonded pairs appear as isolated narrow peaks at small separation. Under elevated temperature and pressure conditions, however, this peak isolation disappears, leading to considerable apparent bonding ambiguity. Using molecular dynamics simulation for sulfur as a testing device, we show that removal of thermal distortion even in extremely hot and dense media by steepest-descent quenching on the potential energy hypersurface completely restores peak isolation and removes bonding ambiguity.