Subject: Re: CCL:G94 warning against LANL1DZ

From: [email-masked] (Mike Frisch)
Date: Wed, 19 Jul 1995 09:41:27 -0400 (EDT)

Eric V. Patterson writes:
> 
> Dear Netters-
>         In the G94 User's Reference (pg. 23), a small footnote warns that
> the use of LANL1DZ is "strongly discouraged".  Can someone tell me why? 
> The best I can tell, LANL1DZ and LANL2DZ only differ in the use of D95V for
> the former and D95 for the latter on first row atoms.  Is there some
> general flaw with LANL1DZ that I should be aware of?  Any help is
> appreciated.
> 
> Eric
> 

LAN2 and LAN1 differ in how many electrons are replaced by the ECP for
some elements (near the right in each row of transition metals):  LANL2
includes the next lower s and p electrons in the valence (i.e., does
not replace them with the core potential) and this produces considerably
better reliability.  The note about discouraging LANL1 is at the request
of Jeff Hay; refer to his original papers on these potentials for details.

Mike Frisch