Is there a common orientational order for the liquid phase of tetrahedral molecules?

摘要

The title question is addressed with molecular dynamics simulations for a broad set of molecules:methane (CH_4), neopentane (C(CH_3)_carbon tetrafluoride CF_tetrachloride CCl_silicon tetrachloride (SiCl_4), vanadium tetrachloride (VCl_tin SnCl_carbontetrabromide (CBr_4), and tin tetraiodide (SnI_4). In all cases the sequence of most populated relativeorientations, for increasing distances, is found to be identical: The closest distances correspond toface-to-face followed by a dominant role of edge-to-face, while for larger distances the mainconfiguration is edge-to-edge. The corner-to-face configuration plays an almost negligible role. Therange of orientational order is also similar, with remnants of orientational correlation discernible upto the fourth solvation shell. The equivalence does not only hold in the qualitative terms just statedbut is also quantitative to a large extent once the center-center distance is properly scaled