## Dispersion/Induced Dipole-Induced Dipole/London/Van Der Waals

Andrea Raymundo 1B
Posts: 32
Joined: Wed Nov 15, 2017 3:04 am

### Dispersion/Induced Dipole-Induced Dipole/London/Van Der Waals

$E_{p}\alpha -(\alpha _{1}\alpha_{2})/r^{6}$
could anyone please explain what this is exactly and like how do we use it

Alicia Yu 1A
Posts: 30
Joined: Thu Feb 22, 2018 3:02 am

### Re: Dispersion/Induced Dipole-Induced Dipole/London/Van Der Waals

That is the equation for the interaction potential energy - it is the energy it takes to pull the bonds (induced dipole-induced dipole, dipoles, hydrogen) apart. When two molecules come close together, the two molecules have both attractive (dipoles) and repulsive forces (electron clouds of two molecules). These forces determine the potential energy of the two molecules. This depends on the separation/distance of the molecules, r, as well as the polarizability ($\alpha$) which depends on the number of e- and the size of the atom (if the electrons are loosely held, the potential energy will be smaller).
Ep will always be negative, thus it is always an attractive force.

This video goes more in depth on the equation.