AMBER Archive (2009)
Subject: Re: [AMBER] second derivative matrix
From: Adrian Roitberg (roitberg_at_qtp.ufl.edu)
Date: Mon Feb 09 2009 - 08:29:51 CST
I am not sure what you mean !
A matrix of second derivatives is of course the FIRST derivative of the
first derivative, right ?
Since the first derivatives as computed to get forces, you are in effect
taking the second derivative (cartesian coordinates) of (minus) the forces.
Now, the derivatives themselves are computed analytically. Given the
functional form of the force field, you can write the second derivatives
in a piece of paper, which means you can program them.
Marie Brut wrote:
> Dear AMBER users,
> I asked the same question last week, but I received no answer. If
> somebody had any information, it would really help me:
> Does somebody know the method used to calculate the second derivative
> matrix in nmode?
> Thank you for your help,
> AMBER mailing list
Dr. Adrian E. Roitberg
Quantum Theory Project
Department of Chemistry
Senior Editor. Journal of Physical Chemistry
American Chemical Society
University of Florida PHONE 352 392-6972
P.O. Box 118435 FAX 352 392-8722
Gainesville, FL 32611-8435 Email adrian_at_qtp.ufl.edu
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