CIS frequencies runs crash with "failed to read isroots"
Clicked A Few Times
2:27:04 PM PST - Sun, Feb 15th 2015
I run version 6.5+r26243 (Debian testing).

I'm trying to get CIS frequencies, but whatever I tried so far ended up in a crash of the TDDFT gradient module with "tddft_grad_init: failed to read isroots". I tried the second example from http://nwchemgit.github.io/index.php/Excited-State_Calculations but this did not work either. After adding "symmetry group c1" after geometry, I used as input:

START bf
TITLE "CIS/6-31G* BF optimization frequencies"
GEOMETRY
symmetry group c1
 B 0.0 0.0 0.0
 F 0.0 0.0 1.2
END
BASIS
 * library 6-31G*
END
DFT
 XC HFexch
END
TDDFT
 CIS
 NROOTS 3
 NOTRIPLET
 TARGET 1
END
TASK TDDFT OPTIMIZE
TASK TDDFT FREQUENCIES


If I add "NUMERICAL" after OPTIMIZE and FREQUENCIES, the geometry optimization runs fine, but as soon as the frequencies start, the error hits again.

If the error is not my side, (i) is this a bug in the code? and (ii) how can I force fully numerical frequencies, I assume it tries to compute the second derivatives via numerical derivatio of analytical gradients?

Gets Around
7:01:30 PM PST - Sun, Feb 15th 2015
This completes without errors:

START bf
TITLE "CIS/6-31G* BF optimization frequencies"

GEOMETRY
symmetry group c1
 B 0.0 0.0 0.0
 F 0.0 0.0 1.2
END

BASIS
 * library 6-31G*
END

DFT
 XC HFExch
END

TDDFT
 CIS
 NROOTS 3
 NOTRIPLET
 TARGET 1
 CIVECS
 GRAD
  ROOT 1
 END
END

TASK TDDFT OPTIMIZE
TASK TDDFT FREQUENCIES


I cribbed from QA/tests/bf_cis, which actually seems to be basically the calculation you are trying here but with a somewhat updated input deck. It is properly documented in the NWChem 6.5 online docs: http://nwchemgit.github.io/index.php/Release65:Excited-State_Calculations#GRAD_--_analytical...

The default documentation seems to still be for an older version, so you wouldn't see what is needed: http://nwchemgit.github.io/index.php/Excited-State_Calculations (no mention of grad or civecs).

Clicked A Few Times
10:36:45 AM PST - Wed, Feb 18th 2015
Thanks a lot, problem solved!

Forum Vet
5:46:16 PM PST - Wed, Feb 25th 2015
patch
A patch is now available to address this issue.
Once the patch is applied, you no longer will need to insert the civecs and grad lines in the input file

http://nwchemgit.github.io/images/Tddft_grad.patch.gz


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