[molpro-user] Linear dependent basis

[Kirk Peterson]

John,

I just now noticed you are using cartesian polarization functions. All correlation consistent basis sets
use pure spherical harmonics.  Use of cartesians will certainly give you linear dependency problems
due to the extra functions this adds. This should not be done!  You were just lucky this didn't happen
earlier.

regards,

Kirk


On Jul 12, 2010, at 3:11 AM, John Keith wrote:

> Hi all,
> 
> I'm trying to run single reference ab initio calculations on
> transition metal complexes and build up enough calculations to
> extrapolate to the CBS limit.
> 
> My molecule is the PdCl4 dianion, and I'm using the Stuttgart Pd
> pseudopotential and the (aug)-cc-pvNZ basis sets on all other valence
> electrons. All are taken from the EMSL basis set library. I get SCF
> convergence with cc-pvDZ, aug-cc-pvDZ, cc-pvTZ, and aug-cc-pvTZ basis
> sets, but at cc-pvQZ I run into an error saying:
> 
> ------------------------
> Eigenvalues of metric
> 
>         1 0.212E-08 0.406E-05 0.681E-05 0.681E-05 0.835E-05 0.102E-04
> 0.103E-04 0.106E-04
> 
> ERROR: BASIS LINEARLY DEPENDENT OR WRONG S
> 
> The current threshold for the smallest tolerated eigenvalue of S is   1.0D-08
> ------------------------
> 
> I spent some time searching the user-list and google, and I couldn't
> find a solution I needed.  What I gather is that since my geometries
> are reasonable, the jobs run fine with smaller basis sets, and since I
> only have one eigenvalue below the threshold, this error probably just
> comes from the fact my QZ basis is (not surprisingly) linearly
> dependent and should be scaled down one or a few basis functions.
> 
> Pardon the naive question, but does someone know the "right" way to
> modify this basis set so it is not linearly dependent, but that it is
> also of desired quality for a meaningful CBS extrapolation? Is it as
> straightforward as starting at the QZ basis and removing individual
> diffuse functions until the basis set is not linearly dependent, or is
> there a higher art to it?
> 
> My input file is:
> ***Pd_4Cl
> 
> cartesian
> 
> geomtyp=xyz
> orient,mass
> geometry={
> 5
> Pd_4Cl calc
> Pd   -0.213992    0.027380   -0.117721
> Cl   -1.943705   -1.515957    0.437439
> Cl    1.304488   -1.784426   -0.423439
> Cl    1.515859    1.570547   -0.672946
> Cl   -1.732472    1.839247    0.188003
> }
> set,charge=-2
> 
> <BASIS>
> 
> hf
> 
> In my <BASIS> block, I've been using a script to pasting the explicit
> basis sets from the EMSL website into the input file. I don't want to
> paste all those messy numbers here unless that's actually requested.
> 
> Thanks in advance!
> 
> --john
> 
> #####################################################################
> Ph D. John A. Keith
> Institut für Elektrochemie     Email: john.keith at uni-ulm.de
> Universität Ulm                    Telephone: +49-731-50-26061
> Albert-Einstein-Allee 47       URL: http://www.wag.caltech.edu/home/johnk
> Ulm D-89069                       URL:
> http://www.uni-ulm.de/theo_echem/index.shtml
> #####################################################################
> There is as much difference between us and ourselves as between us and others.
> 
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