[molpro-user] DF-LCCSD(T) problem: crash with larger basis set

Tue Feb 12 13:34:35 GMT 2013

Hi Joachim,

thanks for the feedback. 

Is there any way I could check whether or not the HF is converged to the 
correct state? Maybe I miss something here but I thought as it is a closed 
shell molecule I only have paired electrons and hence only one spin state?
I am not using Cr or a transition metal but Al so I don't really see how I 
could converge to a different state? I know Gaussian has something like the 
'stable' keyword which is testing whether or not the SCF is 'correct'. Is 
there a similar feature in Molpro?

As for (ii): as I am currently doing a LCCSD calculation that possible problem 
should be eliminated I hope.

Thanks for your sentiments!

All the best from London

Jörg

On Tuesday 12 February 2013 13:26:13 you wrote:
> I have no idea what's wrong, but possibilities are:
> 
> (i) wrong state, perhaps HF converged to a wrong state and there is a lower
> one? (ii) insufficient fitting basis
> 
> Other remark: Using DF-HF is probably much faster than direct HF, in
> particular for larger basis sets.
> 
> Best regards
> Joachim Werner
> 
> > Dear all,
> > 
> > I am currently trying to perform some single point DF-LCCSD(T)
> > calculations on an organometallic compound.
> > 
> > At the DF-LCCSD(T)/cc-pVDZ level of theory, the calculation runs smooth
> > without any problems and I get my single point energy.
> > 
> > However, when I am trying to run the same calculation at the
> > DF-LCCSD(T)/cc- pVTZ level, the calculation crashes in the CCSD part:
> > Minimum memory for LCCSD:    38.40 MW, used:    200.00 MW, max:    389.90
> > MW
> > 
> > ITER.      SQ.NORM     CORR.ENERGY   TOTAL ENERGY   ENERGY CHANGE       
> > DEN1 VAR(S)    VAR(P)  DIIS     TIME
> > 
> >   1      2.00665126    -2.99296600  -941.60036694     0.05725124
> > 
> > -2.92306557  0.11D-01  0.16D-01  1  1  4454.17
> > 
> >   2      2.00663902    -5.22692889  -943.83432983    -2.23396289
> > 
> > 0.00001279  0.53D-03  0.65D+00  2  2  4521.51
> > 
> >   3      2.00603281    -5.22667989  -943.83408083     0.00024900
> > 
> > 0.00001475  0.57D-03  0.65D+00  3  3  4585.54
> > 
> >   4      2.00602946    -5.25966260  -943.86706354    -0.03298271
> > 
> > 0.00002130  0.10D-02  0.66D+00  4  4  4649.57
> > 
> >   5      2.00442950    -5.43585382  -944.04325475    -0.17619122
> > 
> > 0.00008619  0.55D-03  0.71D+00  5  5  4713.17
> > 
> >   6      2.00450932    -5.15168470  -943.75908563     0.28416912
> > 
> > 0.00002367  0.10D-02  0.65D+00  6  6  4780.77
> > 
> >   7  12750.36999404    -5.75382440  -944.36122534    -0.60213970
> > 
> > 0.47490011  0.73D-03  0.84D+00  6  1  4850.68
> > 
> > UNREASONABLE NORM. CALCULATION STOPPED
> > 
> > Norm of t1 vector:     13.76970764      S-energy:     0.00001516
> > Norm of t2 vector:    112.07035801      P-energy:    -2.99387560
> > 
> > ?ERROR: NO CONVERGENCE. TRIPLES WILL NOT BE DONE. THIS CAN BE AVOIDED
> > USING THE NOCHECK OPTION.
> > 
> > RESULTS
> > =======
> > 
> >  LCCSD singles energy                 -0.003213334121
> >  LCCSD singlet pair energy            -2.848042961511
> >  LCCSD triplet pair energy            -3.097983757676
> >  
> >  LCCSD strong pair energy             -5.750611063722
> >  LMP2 close pair energy               -0.110540018435
> >  LMP2 weak pair energy                -0.082516374676
> >  LMP2 distant pair energy             -0.002359262354
> >  
> >  
> >  Reference energy                   -938.607400937737
> >  
> >  LCCSD correlation energy             -5.949240053308
> > 
> > !LCCSD total energy                 -944.556640991046
> > 
> > Program statistics:
> > 
> > Available memory in ccsd:           198929165
> > Min. memory needed in ccsd:          38401396
> > Max. memory used in ccsd:           199999901
> > 
> > ? Error
> > ? No convergence. This error exit can be avoided using the NOCHECK option
> > ? The problem occurs in ccsd_loc
> > 
> > My input file is like that (minus the coordinates):
> > memory,200,m
> > SET,CHARGE=1    !charge of the molecule is +1
> > ! SET,ZSYMEL=NOSYM ! turn off symmetry
> > geomtyp=xyz
> > geometry
> > 
> >   45
> > 
> > [ ... ]
> > gdirect                    !direct calculations
> > hf,maxit=300
> > hf,direct
> > basis=cc-pVTZ              !cc-pVTZ basis set for all elements
> > hf                         !Perform HF calculation
> > DF-lccsd(t)                !Perform L-CCSD(T) calculation with density
> > fitting
> > 
> > 
> > I am currently trying to run a pure LCCSD with the same basis set but I
> > was running out of scratch space. :-(
> > 
> > Is there something wrong with my input or is there a 'problem' with the
> > molecule. The geometry has been calculated at the M11/6-311G(d,p) level
> > of theory and a frequency calculation indicates a minimum on the PES.
> > However, I got to admit, I am not really trusting the DFT calculations
> > here and hence the CCSD(T) calculation. It is a closed shell compound
> > with Al as the metal.
> > 
> > Does anybody got an idea here?
> > 
> > All the best from a cold London
> > 
> > Jörg

-- 
*************************************************************
Jörg Saßmannshausen
University College London
Department of Chemistry
Gordon Street
London
WC1H 0AJ 

email: j.sassmannshausen at ucl.ac.uk
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