Molecular archaeology: Searching for buried connections between microscopic and macroscopic properties of the...

Many macroscopic phenomena and patterns observed in common experience can be associated with unseen processes and/or structures operating at the submicroscopic level of atoms and molecules. The process of unearthing and identifying these hidden microscopic activities and structures-which we shall loosely term molecular archaeology-can reveal interesting, and in some cases informative, scientific principles. The pattern exhibited by the boiling points of the halomethanes is taken as an example. A correlation is noted between the strengths of microscopic binary complexes of these compounds and their macroscopic experimental boiling points. In addition, the use of molecular surface electrostatic potential statistical quantities allows for a dual-parameter relationship between experimentally-determined boiling points for methane and the twelve fluoro-, chloro- and bromo-methanes of interest in this study, using variables for size (volume) and self-interaction capability.

The thirteen molecules included in this study (methane and the four mono- to tetra halomethanes, where the halogen X is F, Cl or Br, were optimized using the ωB97X-D/6-31 + G(d,p) procedure using Gaussian 09. Dimer binding energies and surface electrostatic potentials were computed at the same level. The surface electrostatic potentials were computed using the WFA-SAS code.