Author Topic: Format of the Hessian in the hessian File  (Read 3559 times)

twoo@uottawa.ca

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Format of the Hessian in the hessian File
« on: October 30, 2008, 03:58:40 pm »

Does anyone know how what the format of the hessian is that AOFORCE prints out in the hessian file.

In the aoforce output, the Cartesian force constant matrix is printed out in atomic units in lower triangular format.

However, in the hessian file, the numbers are not the same, and the number of elements does not correspond to a lower triangular form.

It seems there is an extra 3N elements in the hessian file (where N is the number of atoms).  My first thought is that the extra elements are the gradients, that doesn't seem to match either.

Thanks in advance for the help.

Tom Woo

University of Ottawa