CCL:G: Frequency Vs Hessian

From: "Antonio G De Crisci" <antonio.decrisci-#-utoronto.ca>
Subject: CCL:G: Frequency Vs Hessian
Date: Wed, 18 Jun 2008 15:28:34 -0400

 Sent to CCL by: "Antonio G De Crisci" [antonio.decrisci^^^utoronto.ca]
 Hello,
 Can somebody tell me the difference between a frequency calculation in Gaussian
 compared to a hessian calculation (with vibrational analysis) in PC GAMESS?
 Also, in GAMESS, when performing a hessian, I have two method options: numeric
 or analytic. When I choose the numeric size, I have an option of changing the
 displacement size. What is the difference between the two, and what value of the
 displacement size (default= 0.01) would be suitable for a B3LYP/6-311G.
 Thanks,
 Antonio De Crisci
 University of Toronto