2019-01-25 11:39:31 +01:00
|
|
|
|
.\" Man page generated from reStructuredText.
|
|
|
|
|
|
.
|
2019-02-06 18:22:08 +01:00
|
|
|
|
.TH "EXCITED_STATES" "1" "Feb 06, 2019" "2.0" "Quantum Package"
|
2019-01-25 11:39:31 +01:00
|
|
|
|
.SH NAME
|
|
|
|
|
|
excited_states \- | Quantum Package >
|
|
|
|
|
|
.
|
|
|
|
|
|
.nr rst2man-indent-level 0
|
|
|
|
|
|
.
|
|
|
|
|
|
.de1 rstReportMargin
|
|
|
|
|
|
\\$1 \\n[an-margin]
|
|
|
|
|
|
level \\n[rst2man-indent-level]
|
|
|
|
|
|
level margin: \\n[rst2man-indent\\n[rst2man-indent-level]]
|
|
|
|
|
|
-
|
|
|
|
|
|
\\n[rst2man-indent0]
|
|
|
|
|
|
\\n[rst2man-indent1]
|
|
|
|
|
|
\\n[rst2man-indent2]
|
|
|
|
|
|
..
|
|
|
|
|
|
.de1 INDENT
|
|
|
|
|
|
.\" .rstReportMargin pre:
|
|
|
|
|
|
. RS \\$1
|
|
|
|
|
|
. nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin]
|
|
|
|
|
|
. nr rst2man-indent-level +1
|
|
|
|
|
|
.\" .rstReportMargin post:
|
|
|
|
|
|
..
|
|
|
|
|
|
.de UNINDENT
|
|
|
|
|
|
. RE
|
|
|
|
|
|
.\" indent \\n[an-margin]
|
|
|
|
|
|
.\" old: \\n[rst2man-indent\\n[rst2man-indent-level]]
|
|
|
|
|
|
.nr rst2man-indent-level -1
|
|
|
|
|
|
.\" new: \\n[rst2man-indent\\n[rst2man-indent-level]]
|
|
|
|
|
|
.in \\n[rst2man-indent\\n[rst2man-indent-level]]u
|
|
|
|
|
|
..
|
|
|
|
|
|
.sp
|
2019-01-25 14:54:22 +01:00
|
|
|
|
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.
|
2019-01-25 11:39:31 +01:00
|
|
|
|
.sp
|
2019-01-25 14:54:22 +01:00
|
|
|
|
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.
|
2019-01-25 11:39:31 +01:00
|
|
|
|
.sp
|
2019-01-25 14:54:22 +01:00
|
|
|
|
The \fIQuantum Package\fP doesn’t 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.
|
2019-01-25 11:39:31 +01:00
|
|
|
|
.sp
|
2019-01-25 14:54:22 +01:00
|
|
|
|
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\&.
|
2019-01-25 11:39:31 +01:00
|
|
|
|
.sp
|
2019-01-25 14:54:22 +01:00
|
|
|
|
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.
|
2019-01-25 11:39:31 +01:00
|
|
|
|
.sp
|
|
|
|
|
|
\fBSEE ALSO:\fP
|
|
|
|
|
|
.INDENT 0.0
|
|
|
|
|
|
.INDENT 3.5
|
2019-01-25 14:54:22 +01:00
|
|
|
|
The documentation of the \fBscf()\fP, \fBcis()\fP and
|
|
|
|
|
|
\fBfci()\fP programs.
|
2019-01-25 11:39:31 +01:00
|
|
|
|
.UNINDENT
|
|
|
|
|
|
.UNINDENT
|
|
|
|
|
|
.SH AUTHOR
|
|
|
|
|
|
A. Scemama, E. Giner
|
|
|
|
|
|
.SH COPYRIGHT
|
2019-01-25 14:54:22 +01:00
|
|
|
|
2019, A. Scemama, E. Giner
|
2019-01-25 11:39:31 +01:00
|
|
|
|
.\" Generated by docutils manpage writer.
|
|
|
|
|
|
.
|
