[Columbus] ciudg to do single reference CI (CIS)

[Thomas Mueller]

On Fri, 3 Nov 2017, SPIRIDOULA MATSIKA wrote:

>
> Dear Columbus colleagues,
> I have tried to make Columbus do a CIS calculation using a single reference. It
> seems to me that it cannot be done. I have tried to use
>  IVMODE = 0
>  ISTRT = 1
> to generate initial vectors from both z and y walks but this has not worked. Is
> there a way to do such calculation?
>
> Thank you,
> Spiridoula
>

   Dear Spiridoula,

   this is the way to carry out SR-CIS and MR-CIS.

   The single excitations are defined with respect to one or
   several references. However, it might happen to define a wavefunction
   with no references of correct symmetry and hence  with no CSFs (check
   cidrtls). Under such circumstances allow reference CSFs of all
   symmetries so that all excitations are generated and only
   subsequently subjected to the requested overall symmetry of the
   wavefunction. Default mode of operation is to constrain the references
   to the same symmetry as the requested symmetry of the wavefunction.

  Regards,

  Thomas




>
>
> Spiridoula Matsika
> Professor of Chemistry
> Department of  Chemistry
> Temple University
> 1901 N.13th Street
> 242 Beury Hall
> Philadelphia, PA 19122
>
> Phone: 215 204 7703
> Fax: 215 204 1532
> smatsika at temple.edu
>
>
>

-----------------------------------------------------------
Dr. Thomas Mueller
Institute for Advanced Simulation (IAS)
Juelich Supercomputing Centre (JSC)

Phone:  +49-2461-61-3175
Fax:    +49-2461-61-6656
E-mail: th.mueller at fz-juelich.de
WWW:    http://www.fz-juelich.de/jsc/

JSC is the coordinator of the
John von Neumann Institute for Computing (NIC)
and member of the
Gauss Centre for Supercomputing (GCS)
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