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Problem with CDFT-CI

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Author Post
Member
Registered: Oct 2017
Posts: 1
Dear All,

I am facing a problem in running CDFT-CI calculation in Qchem 4.4 version.

I am considering a dimer system, but even with a monomer molecule I have the same error. I am using the following rem section and cdft input:

$rem
unrestricted true
scf_algorithm rca_diis
max_RCA_cycles 500
METHOD B3LYP
BASIS 6-31+G*
mem_total 4000
mem_static 2000
MAX_SCF_CYCLES 200
SCF_CONVERGENCE 7
cdftci TRUE
cdftci_print 2
cdft_thresh 7
gui 2
IPRINT 200
symmetry off
sym_ignore true
$end

$cdft
1.0
-1 15 26
0.0
-1 15 26 s
----------------
0.0
-1 15 26
-1.0
-1 15 26 s
$end

I am considering -1 charge in one of the fragments in the molecule and accordingly -1 charge has been mentioned in the atom numbers 15 to 26.

I am getting the following error and the job exits:

Starting CDFT-CI SCF calculation on state 1 ...


Q-Chem fatal error occurred in module /home/scratch/svnadmin/11556_zgan/qchem/qparser/read_cdft.C, line 386:

Invalid data format for CDFTCI!


Please let me know if there is an error in the input section.

Thanks in advance!

With regards,
Somananda
Member
Registered: Nov 2017
Posts: 1
Hi Somananda,


A few things to be aware

1) The CDFT-CI routine constraints electrons, and not charges. If you want to constraint one electron (charge -1), then you should have 1 at the beginning of your lines in the $cdft part, and not -1.
2) Apparently the separation between two diabatic states should be separated by three hyphens ( --- ). I don't know how specific this is, as I've never tested with different numbers of hyphens.

Here is a very helpful tutorial available on youtube. This helped me starting with CDFT-CI:

https://www.youtube.com/watch?v=IuF6WFPpaKw


Hope that helps,

Alex

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