# CCL:G: How can I calculate force constants (k) by hessian matrix in
Gaussian

*From*: "Moein Goodarzi"
<moein.goodarzi20(_)gmail.com>
*Subject*: CCL:G: How can I calculate force constants (k) by hessian
matrix in Gaussian
*Date*: Wed, 9 Apr 2014 01:36:47 -0400

Sent to CCL by: "Moein Goodarzi" [moein.goodarzi20]^[gmail.com]
I can fine Cartesian force constant matrix in check-point file of Gaussian. I am
trying to obtain vibration force constants by Cartesian force constant matrix. I
diagonalized this matrix to obtain vibrational force constants. However, I
cannot get the same force constants like the Gaussian results (in mdyne/angstrom
unit).
Sincerely
Moein Goodarzi
Moein.goodarzi20[at]gmail.com
Institute for Advanced Studies in Basic Sciences (IASBS), Zanjan, Iran