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mirror of https://github.com/QuantumPackage/qp2.git synced 2024-11-18 11:23:38 +01:00
qp2/man/excited_states.1
Anthony Scemama 49e9488f62
Develop (#10)
* fixed laplacian of aos

* corrected the laplacians of aos

* added dft_one_e

* added new feature for new dft functionals

* changed the configure to add new functionals

* changed the configure

* added dft_one_e/README.rst

* added README.rst in new_functionals

* added source/programmers_guide/new_ks.rst

* Thesis Yann

* Added gmp installation in configure

* improved qp_e_conv_fci

* Doc

* Typos

* Added variance_max

* Fixed completion in qp_create

* modif TODO

* fixed DFT potential for n_states gt 1

* improved pot pbe

* trying to improve sr PBE

* fixed potential pbe

* fixed the vxc smashed for pbe sr and normal

* Comments in selection

* bug fixed by peter

* Fixed bug with zero beta electrons

* Update README.rst

* Update e_xc_new_func.irp.f

* Update links.rst

* Update quickstart.rst

* Update quickstart.rst

* updated cipsi

* Fixed energies of non-expected s2 (#9)

* Moved diag_algorithm in Davdison
2019-02-22 19:19:58 +01:00

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.TH "EXCITED_STATES" "1" "Feb 06, 2019" "2.0" "Quantum Package"
.SH NAME
excited_states \- | Quantum Package >
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.sp
It is possible to run excited states calculations with the quantum
package. To do this, set \fBdeterminants n_states\fP to the number
of requested states. The selection criterion will be the maximum of the
selection criteria for each state. If the Davidson diagonalization has
difficulties to converge, increase the \fBdavidson n_states_diag\fP
value.
.sp
When computing multiple states, it is good to have the
\fBdeterminants s2_eig\fP flag \fBtrue\fP\&. This will force the Davidson
algorithm to choose only vectors with a value of \ewidehat{S^2} equal to
\fBdeterminants expected_s2\fP\&. Otherwise, different spin states
will come out in the diagonalization.
.sp
The \fIQuantum Package\fP doesnt take account of the symmetry. Due to numerical noise,
excited states of different symmetries may enter in the calculation.
Note that it is possible to make state\-average calculation of states
with different symmetries and/or different spin multiplicities.
.sp
To include excited state of all possible symmetries, a simple trick is
to run a preliminary multi\-state CIS calculation using the CIS
program, and then running the selected FCI restarting from the CIS
states, setting \fBdeterminants read_wf\fP to \fBtrue\fP\&.
.sp
Usually, it is good practice to use state\-averaged natural MOs so that
all states have MOs of comparable quality. This allows for a faster
convergence of excitation energies.
.sp
\fBSEE ALSO:\fP
.INDENT 0.0
.INDENT 3.5
The documentation of the \fBscf()\fP, \fBcis()\fP and
\fBfci()\fP programs.
.UNINDENT
.UNINDENT
.SH AUTHOR
A. Scemama, E. Giner
.SH COPYRIGHT
2019, A. Scemama, E. Giner
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