Cohesive energy of a crystal is the energetic cost that holds
all atoms together in a crystal. It can be determined both
experimentally and theoretically. Explain, based on your knowledge
on the quantum mechanical nature of non–covalent interactions, why
the following statement is incorrect:
Because silicon crystal are bonded together by strong covalent
bonds between silicon atoms, non– covalent interactions, in
particular, dispersion interactions, play NO role in determining
the cohesive energy in silicon crystals.