# CCL: a really silly question

• From: Igors Mihailovs <igors.mihailovs0|,|gmail.com>
• Subject: CCL: a really silly question
• Date: Fri, 13 May 2016 12:08:25 +0300

Dear Mr Wood,

In addition to what was said by Mr Shobe, you have 3.15e-8 in your _expression_, while it should read 3.15e-10 (angstroem is 10^-10 m); also, charges should be multiplied not only with 10^-19, but with 1.60218e-19.

With best wishes,
Igors Mihailovs (engineer / PhD student)
Institute of Solid State Physics
University of Latvia

2016-05-12 20:56 GMT+03:00 David Shobe http://avidshobe_-_yahoo.com">avidshobe_-_yahoo.com :
The formula is E = (1 / 4 pi E0) (q1 q2 / r12).   Thus your conversion factor is 1 / (4 pi E0) where E0 = 8.854 187 817... x 10-12  J^-1 C^2 m-1.
Sorry for the lack of typography.

On Thursday, May 12, 2016 10:33 AM, Richard Leo Wood rwoodphd##msn.com <owner-chemistry+/-ccl.net> wrote:

Sent to CCL by: "Richard Leo Wood" [rwoodphd ~~ msn.com]
I am trying to compute the electrostatic interaction for a pair of atoms
> from an energy minimized structure.

I have the charges on the two atoms as -0.47 and -0.55.  They are 3.15
Angstroms apart.  So, E = (-0.55*-0.45)e-38 C^2/3.15e-8 m.

I get 8.21e-32 C^2/m.  My question is how do I convert this to Joules?

Richard

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