LET — Do not reduce gradients in FORCE.
In cases where the force constant matrix is computed by invocation of FORCE, AMPAC will calculate the gradients of the input geometry and halt execution if the gradient norm is not less than 3.0 to ensure that the computation is carried out on a fully minimized geometry. The LET keyword allows the calculation to be completed without regard to this test. It should be emphasized that force constants at any place other than a fully optimized stationary point are undefined. LET should be used with extreme care. See Chapter 4, Computational Procedures for a discussion of stationary point characterization.
Copyright © 1992-2013 Semichem, Inc. All rights reserved.