Subject: DFT frequency scaling factor <SUMMARY>

From: Dongchul Lim <[email-masked]>
Date: Fri, 6 Oct 95 13:41:27 EDT

I'd like to thank those who replied to my question
regarding DFT frequency scaling factors.
-Dongchul Lim, [email-masked]

>Are there scaling factors for frequencies from different
>DFT methods, especially BECKE3LYP?

--------------------------------------------------------------------
   The scaling factor for BECKE3LYP seems pretty close to one, 0.989
according to one study, see:
  C. W. Bauschlicher and H. Partridge, J. Chem. Phys. 98 (1994) 11623.
   I think that even for non-empirical functionals (LDA, Perdew's GGA)
scaling factors would not help much (they would probably turn out
close to one).
 |-------------------------------|-----------------------------|
 | Rene Fournier                 |  [email-masked]  |
 | Department of Physics         |  [email-masked]   |
 | University of Nevada          |  phone : (702) 895 1706     |
 | Las Vegas, NV 89154-4002 USA  |  FAX   : (702) 895 0804     |
 |-------------------------------|-----------------------------|

--------------------------------------------------------------------
For the B-LYP method, the scaling factor is close to one. However, a scale 
factor of 0.9613 is required for the Becke3LYP method for reliable prediction 
of fundamental frequencies. The 0.9613 value was derived from comparison with
experimental frequencies of a large set of molecules (1066 frequencies for 122 
molecules). 

 ++~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~++
 ||         __  |\         Dr. Ming Wah (Richard) Wong                    ||
 ||        /  |_| \        -----------------------------------------------||
 ||      .'        \       Department of Chemistry                        ||
 ||     /          *\      The University of Queensland                   ||
 ||     \     __    /      Brisbane, Qld 4072, Australia                  ||
 ||      \_.-'  \_ /       Fax: +61 7 3365 4299 | Phone: +61 7 3365 3829  ||
 ||               v        email address: [email-masked]    ||
 ++~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~++

--------------------------------------------------------------------