[molpro-user] Simple unreasonable norm problem...
Kirk Peterson
kipeters at wsu.edu
Fri Oct 15 16:20:22 BST 2010
Charlie,
probably this is just due to RHF and CCSD not being very happy dissociating your molecule from an overall singlet to two
doublet atoms (and a closed-shell Ca2+). But outside of that, please realize that the default frozen core for Ca
is [Ar], so that your calculation only involves 2 correlated electrons. So the (T) in your input is redundant since CCSD
already corresponds to a FCI. I would recommend using the MRCI program, presumably with some sort of CASSCF orbitals,
which will not have any problems dissociating this molecule.
regards,
Kirk
PS - perhaps with the small VDZ basis set, one of the charges on Ca is transferring to an H? Certainly the IP of H is larger
than the 2nd IP of Ca, but maybe not with this basis set.
On Oct 14, 2010, at 10:38 AM, Charles Wood wrote:
> Hi Molpro mailling list,
>
> I apologise in advance if this is a simple problem to fix. I looked on
> the mailing list's previous thread to no avail.
>
> My problem is this:
> I am trying to run an extremely simple H - Ca2+ - H calculation (one
> calcium 2+ ion centred between 2 hydrogen atoms). I'm using UHF and
> UCCSD(T) programs in molpro2009.1. If the geometry is specified so each
> of the H atoms are less than 1.5 Angstroms then the calculation works fine.
>
> If the H atoms are equal to or more than 1.5 Angstroms from the Ca2+
> ion, I get an unreasonable norm and an unconverged calculation. The
> input file and output error are at the tail of this message.
>
> I saw some people suggest 'shift' but this looks like something
> connected to the geometry....any idea??
>
> Thank you for any help!
> Charlie
> *************
> INPUT:
> *************
> ***,HHCa
> memory,64,mw
> print,basis,orbitals
>
> geomtyp = xyz
> symmetry,nosym
> angstrom
> geometry={
> 3,
>
> h -1.5 0.0 0.0
> h 1.5 0.0 0.0
> ca 0.0 0.0 0.0
> end
> }
>
> basis=vdz
> wf,20,1,0
>
> rhf
> uccsd(t)
> ---
>
> *****************
> OUTPUT ERROR:
> *****************
> Starting UCCSD calculation
>
> ITER. SQ.NORM CORR.ENERGY TOTAL ENERGY ENERGY
> CHANGE DEN1 VAR(S) VAR(P) DIIS TIME
> 1 1.09064786 -0.06995192 -676.96454186 -0.06995192
> -0.01242820 0.11D-02 0.11D-01 1 1 0.02
> 2 1.19987435 -0.09555561 -676.99014555 -0.02560369
> -0.00078764 0.17D-03 0.36D-03 2 2 0.02
> 3 1.20574077 -0.09615967 -676.99074961 -0.00060406
> -0.00003603 0.21D-04 0.11D-04 3 3 0.03
>
> UNREASONABLE NORM. CALCULATION STOPPED
>
> Norm of t1 vector: 0.08966229 S-energy: 0.00000000
> T1 diagnostic: 0.04483114
>
> D1 diagnostic: 0.06340081
> Norm of t2 vector: 0.44463631 P-energy: -0.09615967
> Alpha-Beta: -0.09615967
> Alpha-Alpha: 0.00000000
> Beta-Beta: 0.00000000
>
> Doubles amplitudes (print threshold = 0.500E-01):
>
> I J SYM. A SYM. B A B T(IJ,
> AB) [Alpha-Beta]
>
> 1 1 1 1 1 1 -0.41754002
> 1 1 1 1 1 9 -0.06746129
> 1 1 1 1 1 20 0.06808800
> 1 1 1 1 9 1 -0.06746129
> 1 1 1 1 20 1 0.06808800
>
> ?ERROR: NO CONVERGENCE. TRIPLES WILL NOT BE DONE. THIS CAN BE AVOIDED
> USING THE NOCHECK OPTION.
>
> Spin contamination <S**2-Sz**2-Sz> 0.00000000
>
>
> RESULTS
> =======
>
> Reference energy -676.894589937024
> UCCSD singles energy 0.000000003496
> UCCSD pair energy -0.096159674326
> UCCSD correlation energy -0.096159670830
>
> !RHF-UCCSD energy -676.990749607853
>
> Program statistics:
>
> Available memory in ccsd: 63999882
> Min. memory needed in ccsd: 28044
> Max. memory used in ccsd: 28044
> Max. memory used in cckext: 52759 ( 3 integral passes)
> Max. memory used in cckint: 134726 ( 1 integral passes)
>
>
> ? Error
> ? No convergence. This error exit can be avoided using the NOCHECK option
> ? The problem occurs in ccsd
>
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