What determines the point of interaction for molecular interactions?

The point of interaction for molecular interactions is primarily determined by the frontier orbitals, which are the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). These orbitals play a crucial role in chemical bonding and molecular interactions because they indicate the regions of space where the most significant electron density is found and where electron transitions can occur.

When two molecules approach each other, their HOMOs and LUMOs interact, which influences how they bond and the strength of that bond. For instance, if the HOMO of one molecule can overlap effectively with the LUMO of another, a strong interaction can occur, leading to bond formation. This concept is fundamental in understanding reaction mechanisms, coordination chemistry, and other aspects of molecular interactions.

The other factors mentioned—like the number of layers in a molecule, the kinetic energy of interacting molecules, and the atomic radius—while they can influence molecular behavior and properties, do not directly dictate the point of interaction in the same way that the frontier orbitals of the participating molecules do. These other factors might affect stability, reactivity, or steric hindrance, but they are not the principal determinants of how and where the molecular interaction occurs in terms of electron exchange.