(*Dipole moment of the lone electronic pair, carbon and fluorine*)
dzeta=1.625
momdip1=10/Sqrt[3]/dzeta*lambda/(1+lambda^2)
dzeta2=2.60
momdip2=10/Sqrt[3]/dzeta2*lambda/(1+lambda^2)
Plot[{momdip1,momdip2},{lambda,0,10}]