van der Waals interactions

Defining as the distance of separation for which and as the depth of potential well, Lennard-Jones derived expressions for Bvdw and Brep leading to what we now call “Lennard-Jones potential”

])()[(4 6126

12

rrr

B

r

B repvdw

Approximation: spherical

1

h

BEvdw

2

B2 = aAeff/12 (under the Derjaguin approximation in the non-retarded limit) Aeff: Hamaker constant

Simplified form: