Polyacetylene: Singularity in Pulay matrix. Error and Fock matrices removed

From NWChem

Viewed 843 times, With a total of 2 Posts
Jump to: navigation, search

Clicked A Few Times
Threads 8
Posts 11
Hello,
I am trying to calculate the raman spectra for polyacetylene chains of different lengths.
When I got to chains with 10 atoms I started getting the following error:


                             NWChem Input Module
-------------------

Raman Analysis
--------------
NWChem Nuclear Hessian and Frequency Analysis
---------------------------------------------
NWChem Analytic Hessian
-----------------------
NWChem DFT Module
-----------------
TDDFT c10 B3LYP/6-31G*
...
  convergence    iter        energy       DeltaE   RMS-Dens  Diis-err    time
---------------- ----- ----------------- --------- --------- --------- ------
d= 0,ls=0.0,diis 1 -381.9502973210 -6.85D+02 6.36D-06 1.95D-07 23.4
d= 0,ls=0.0,diis 2 -381.9502971977 1.23D-07 4.70D-06 1.04D-06 23.8
d= 0,ls=0.0,diis 3 -381.9502973405 -1.43D-07 3.04D-07 6.02D-08 24.1
d= 0,ls=0.0,diis 4 -381.9502973409 -4.07D-10 1.13D-07 5.75D-08 24.5
d= 0,ls=0.0,diis 5 -381.9502973410 -6.47D-11 3.12D-08 5.70D-08 24.8
d= 0,ls=0.0,diis 6 -381.9502973410 -6.82D-12 8.60D-09 5.70D-08 25.2
d= 0,ls=0.0,diis 7 -381.9502973410 2.27D-13 2.41D-09 5.70D-08 25.5
d= 0,ls=0.0,diis 8 -381.9502973410 2.27D-13 4.25D-10 5.70D-08 25.8
Singularity in Pulay matrix. Error and Fock matrices removed.
...

I incremented the dft iterations up to 5000 and it still gave me the following error:

hess_anal: energy failure 555
------------------------------------------------------------------------
------------------------------------------------------------------------
current input line :
43: task dft raman
------------------------------------------------------------------------
------------------------------------------------------------------------
This type of error is most commonly associated with calculations not reaching
convergence criteria


Would anyone happen to have some insight as to how to resolve this?
thank you.

Forum Vet
Threads 9
Posts 1580
Could you please post your input file?

Clicked A Few Times
Threads 8
Posts 11
Problem solved
instead of just using "task dft raman"
I started using "task dft raman numerical"


Forum >> NWChem's corner >> Running NWChem



Who's here now Members 0 Guests 1 Bots/Crawler 0


AWC's: 2.5.10 MediaWiki - Stand Alone Forum Extension
Forum theme style by: AWC