Quoting "S. Sanchez" <lcqsigi at gmail.com>: > My question arises given the fact that the dchi/dr tensor can be obtained as > the third order derivative of the Energy (in units of Ry or Ha) with respect > to the atomic displacement (bohr) and two times the electric field (e/bohr). > > dchi/dr=d^3E/(dr*de1*de2) > where E is the Energy; r the displacement, e1 and e2 the electric fields.
I don't have here my notes, but e^2/8\pi (e=electric field) is an energy density, i.e. energy per unit volume, so dchi/dr=d^3E/(dr*de1*de2) has the dimension of r^2. P. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.