Question

The formula expressing the force F(r) acting between two neutral molecules is

• A. $F_{\left(r\right)}=\frac{A}{r^{13}}-\frac{B}{r^7}$
• B. $F_{\left(r\right)}=\frac{A}{r^{12}}-\frac{B}{r^6}$
• C. $F_{\left(r\right)}=\frac{A}{r^7}+\frac{B}{r^{13}}$
• D. $F_{\left(r\right)}=\frac{A}{r^6}+\frac{B}{r^{12}}$

Answer 1

The correct option is A $F_{\left(r\right)}=\frac{A}{r^{13}}-\frac{B}{r^7}$

The Lennard-Jones Potential is given by the following equation:

$V=\frac{A}{r^{12}}-\frac{B}{r^6}$

$Now,F=-\frac{dV}{dr}=\frac{A}{r^{13}}-\frac{B}{r^7}$

(merging constants with A and B)