1CHEMPS2(1)                      chemps2 v1.8.9                      CHEMPS2(1)
2
3
4

NAME

6       chemps2 - spin-adapted DMRG for ab initio quantum chemistry
7
8

SYNOPSIS

10       chemps2 [OPTION] ...
11
12

DESCRIPTION

14       chemps2  is  a  scientific  code to perform spin-adapted density matrix
15       renormalization group (DMRG) calculations for ab initio  quantum  chem‐
16       istry  fcidump  files. This method allows one to obtain numerical accu‐
17       racy in active spaces beyond the  capabilities  of  full  configuration
18       interaction  (FCI)  and  can return the active space 2-, 3-, and 4-RDM.
19       The method is therefore ideal to replace the FCI solver in the complete
20       active  space  self consistent field (CASSCF) and complete active space
21       second order perturbation theory (CASPT2) methods. The link to the user
22       manual can be found in the section SEE ALSO.
23
24

OPTIONS

26   SYMMETRY
27       Conventions for the symmetry group and irrep numbers (same as psi4):
28
29                        |  0    1    2    3    4    5    6    7
30               ---------|-----------------------------------------
31               0 : c1   |  A
32               1 : ci   |  Ag   Au
33               2 : c2   |  A    B
34               3 : cs   |  Ap   App
35               4 : d2   |  A    B1   B2   B3
36               5 : c2v  |  A1   A2   B1   B2
37               6 : c2h  |  Ag   Bg   Au   Bu
38               7 : d2h  |  Ag   B1g  B2g  B3g  Au   B1u  B2u  B3u
39
40   ARGUMENTS
41       -f, --file=inputfile
42              Specify the input file.
43
44       -v, --version
45              Print the version of chemps2.
46
47       -h, --help
48              Display this help.
49
50   INPUT FILE
51       FCIDUMP = /path/to/fcidump
52              Note  that orbital irreps in the FCIDUMP file follow molpro con‐
53              vention!
54
55       GROUP = int
56              Set the psi4 symmetry group number [0-7]  which  corresponds  to
57              the FCIDUMP file.
58
59       MULTIPLICITY = int
60              Overwrite the spin multiplicity [2S+1] of the FCIDUMP file.
61
62       NELECTRONS = int
63              Overwrite the number of electrons of the FCIDUMP file.
64
65       IRREP = int
66              Overwrite  the  target  wavefunction  irrep [0-7] of the FCIDUMP
67              file (psi4 convention).
68
69       EXCITATION = int
70              Set which excitation should be calculated. If zero,  the  ground
71              state is calculated (default 0).
72
73       SWEEP_STATES = int,int,int
74              Set the number of reduced renormalized basis states for the suc‐
75              cessive sweep instructions (positive integers).
76
77       SWEEP_ENERGY_CONV = flt,flt,flt
78              Set the energy convergence to stop the successive sweep instruc‐
79              tions (positive floats).
80
81       SWEEP_MAX_SWEEPS = int,int,int
82              Set  the  maximum  number  of  sweeps  for  the successive sweep
83              instructions (positive integers).
84
85       SWEEP_NOISE_PREFAC = flt,flt,flt
86              Set the noise prefactors for the successive  sweep  instructions
87              (floats).
88
89       SWEEP_DVDSON_RTOL = flt,flt,flt
90              Set  the  residual norm tolerance for the Davidson algorithm for
91              the successive sweep instructions (positive floats).
92
93       NOCC = int,int,int,int
94              Set the number of occupied (external core)  orbitals  per  irrep
95              (psi4 irrep ordering).
96
97       NACT = int,int,int,int
98              Set  the  number of active orbitals per irrep (psi4 irrep order‐
99              ing).
100
101       NVIR = int,int,int,int
102              Set the number of virtual (secondary) orbitals per  irrep  (psi4
103              irrep ordering).
104
105       MOLCAS_2RDM = /path/to/2rdm/output
106              When  all  orbitals  are active orbitals, write out the 2-RDM in
107              HDF5 format when specified (default unspecified).
108
109       MOLCAS_3RDM = /path/to/3rdm/output
110              When all orbitals are active orbitals, write out  the  3-RDM  in
111              HDF5 format when specified (default unspecified).
112
113       MOLCAS_F4RDM = /path/to/f4rdm/output
114              When  all orbitals are active orbitals, write out the 4-RDM con‐
115              tracted with the Fock operator in  HDF5  format  when  specified
116              (default unspecified).
117
118       MOLCAS_FOCK = /path/to/fock/input
119              When  all  orbitals  are active orbitals, read in this file con‐
120              taining the Fock operator (default unspecified).
121
122       MOLCAS_FIEDLER = bool
123              When  all  orbitals  are  active  orbitals,  switch  on  orbital
124              reordering  based  on  the Fiedler vector of the exchange matrix
125              (TRUE or FALSE; default FALSE).
126
127       MOLCAS_ORDER = int,int,int,int
128              When all orbitals are active orbitals, provide a custom  orbital
129              reordering  (default  unspecified).  When specified, this option
130              takes precedence over MOLCAS_FIEDLER.
131
132       MOLCAS_OCC = int,int,int,int
133              When all orbitals are active orbitals, set initial guess  to  an
134              ROHF  determinant  (default unspecified). The occupancy integers
135              should be 0, 1 or 2  and  the  orbital  ordering  convention  is
136              FCIDUMP.
137
138       MOLCAS_MPS = bool
139              When all orbitals are active orbitals, switch on the creation of
140              MPS checkpoints (TRUE or FALSE; default FALSE).
141
142       MOLCAS_STATE_AVG = bool
143              Switch on writing to disk of N-RDMs of intermediate roots  (TRUE
144              or FALSE; default FALSE).
145
146       SCF_STATE_AVG = bool
147              Switch on state-averaging (TRUE or FALSE; default FALSE).
148
149       SCF_DIIS_THR = flt
150              Switch  on  DIIS  when the update norm is smaller than the given
151              threshold (default 0.0).
152
153       SCF_GRAD_THR = flt
154              Gradient norm threshold for convergence of the DMRG-SCF  orbital
155              rotations (default 1e-6).
156
157       SCF_MAX_ITER = int
158              Specify the maximum number of DMRG-SCF iterations (default 100).
159
160       SCF_ACTIVE_SPACE = char
161              Rotate  the  active space orbitals: no additional rotations (I),
162              natural orbitals (N), localized and  ordered  orbitals  (L),  or
163              ordered orbitals only (F) (default I).
164
165       SCF_MOLDEN = /path/to/molden
166              Rotate  the  FCIDUMP orbitals to the DMRG-SCF occupied (external
167              core), active, and virtual (secondary) orbitals.
168
169       CASPT2_CALC = bool
170              Switch on the CASPT2 calculation (TRUE or FALSE; default FALSE).
171
172       CASPT2_ORBS = char
173              Perform  the   DMRG   calculation   for   the   4-RDM   in   the
174              SCF_ACTIVE_SPACE orbitals (A) or in the pseudocanonical orbitals
175              (P) (default A).
176
177       CASPT2_IPEA = flt
178              Ionization potential - electron affinity shift (default 0.0).
179
180       CASPT2_IMAG = flt
181              Imaginary level shift (default 0.0).
182
183       CASPT2_CHECKPT = bool
184              Create checkpoints to continue the CASPT2 4-RDM calculation over
185              multiple runs (TRUE or FALSE; default FALSE).
186
187       CASPT2_CUMUL = bool
188              Use  a cumulant approximation for the CASPT2 4-RDM and overwrite
189              CASPT2_CHECKPT to FALSE (TRUE or FALSE; default FALSE).
190
191       PRINT_CORR = bool
192              Print correlation functions (TRUE or FALSE; default FALSE).
193
194       TMP_FOLDER = /path/to/tmp/folder
195              Overwrite the tmp folder for the  renormalized  operators.  With
196              MPI,  separate  folders  per process can (but do not have to) be
197              used (default /tmp).
198
199   EXAMPLE
200        $ cd /tmp
201        $ wget 'https://github.com/SebWouters/CheMPS2/raw/master/tests/matrixelements/N2.CCPVDZ.FCIDUMP'
202        $ ls -al N2.CCPVDZ.FCIDUMP
203        $ wget 'https://github.com/SebWouters/CheMPS2/raw/master/tests/test14.input'
204        $ sed -i "s/path\/to/tmp/" test14.input
205        $ cat test14.input
206        $ chemps2 --file=test14.input
207
208

AUTHOR

210       Written by Sebastian Wouters <sebastianwouters@gmail.com>
211
212

BUGS

214       Reporting bugs: https://github.com/sebwouters/CheMPS2/issues
215
216

SEE ALSO

218       User manual: http://sebwouters.github.io/CheMPS2/index.html
219
220
222       CheMPS2: a spin-adapted implementation of DMRG for ab initio quantum chemistry
223       Copyright (C) 2013-2018 Sebastian Wouters
224
225       This program is free software; you can redistribute it and/or modify
226       it under the terms of the GNU General Public License as published by
227       the Free Software Foundation; either version 2 of the License, or
228       (at your option) any later version.
229
230       This program is distributed in the hope that it will be useful,
231       but WITHOUT ANY WARRANTY; without even the implied warranty of
232       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
233       GNU General Public License for more details.
234
235       You should have received a copy of the GNU General Public License along
236       with this program; if not, write to the Free Software Foundation, Inc.,
237       51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
238
239
240
241
242version 1.8.9                   29 October 2018                     CHEMPS2(1)
Impressum