mirror of
https://github.com/LCPQ/quantum_package
synced 2024-06-02 11:25:26 +02:00
72 lines
2.5 KiB
Groff
72 lines
2.5 KiB
Groff
.\" Man page generated from reStructuredText.
|
|
.
|
|
.TH "CIS" "1" "Jan 16, 2019" "2.0" "Quantum Package"
|
|
.SH NAME
|
|
cis \- | 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
|
|
..
|
|
.INDENT 0.0
|
|
.INDENT 3.5
|
|
Configuration Interaction with Single excitations.
|
|
.sp
|
|
This program takes a reference Slater determinant of ROHF\-like occupancy, and performs all single excitations on top of it. Disregarding spatial symmetry, it computes the \fIn_states\fP lowest eigenstates of that CI matrix. (see \fBdeterminants n_states\fP)
|
|
.sp
|
|
This program can be useful in many cases:
|
|
.sp
|
|
Ground state calculation
|
|
.sp
|
|
To be sure to have the lowest SCF solution, perform an \&.scf. (see the hartree_fock module), then a \fI\%cis\fP, save the natural orbitals (see \&.save_natorb.) and re\-run an \&.scf. optimization from this MO guess.
|
|
.sp
|
|
Excited states calculations
|
|
.sp
|
|
The lowest excited states are much likely to be dominated by single\-excitations. Therefore, running a \fI\%cis\fP will save the \fIn_states\fP lowest states within the CIS space in the \fI\%EZFIO\fP directory, which can afterwards be used as guess wave functions for a further multi\-state FCI calculation if \fBdeterminants read_wf\fP is set to \fBtrue\fP before running the \&.fci. executable.
|
|
.sp
|
|
If \fBdeterminants s2_eig\fP is set to \fBtrue\fP, the CIS will only retain states having the expected \ewidehat{S^2} value (see \fBdeterminants expected_s2\fP). Otherwise, the CIS will take the lowest \fBdeterminants n_states\fP, whatever multiplicity they are.
|
|
.sp
|
|
Note
|
|
.sp
|
|
To discard some orbitals, use the qp_set_mo_class command to specify:
|
|
.INDENT 0.0
|
|
.IP \(bu 2
|
|
\fIcore\fP orbitals which will be always doubly occupied
|
|
.IP \(bu 2
|
|
\fIact\fP orbitals where an electron can be either excited from or to
|
|
.IP \(bu 2
|
|
\fIdel\fP orbitals which will be never occupied
|
|
.UNINDENT
|
|
.UNINDENT
|
|
.UNINDENT
|
|
.sp
|
|
File: \fBcis/cis.irp.f\fP
|
|
.SH AUTHOR
|
|
A. Scemama, E. Giner
|
|
.SH COPYRIGHT
|
|
2018, A. Scemama, E. Giner
|
|
.\" Generated by docutils manpage writer.
|
|
.
|