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
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current input line :
43: task dft raman
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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.
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