Relativistic multireference second-order perturbation theory (RelCASPT2)¶
Description¶
The relativistic version of the fully internally contracted CASPT2. As in its non-relativistic analogue, single-state calculations, multi-state calculations, and its extended variant are available. Of course, this is implemented with the automatic code generator SMITH3.
Title: relsmith
Keywords¶
CASSCF keywords¶
See Relativistic complete active space self-consistent field (RelCASSCF).
SMITH keywords¶
The default values are recommended unless mentioned otherwise.
method
Description: Do multistate CASPT2.
Datatype: string
Values:
caspt2
: Standard CASPT2.casa
: Use Dyall’s Hamiltonianms
Description: Do multistate CASPT2.
Datatype: bool
Default: true.
xms
Description: Do extended multistate CASPT2.
Datatype: bool
Default: true.
sssr
Description: Use SS-SR contraction scheme.
Datatype: bool
Default: true.
shift
Description: Vertical shift.
Datatype: double precision
Default: 0.0
thresh
Description: Convergence threshold.
Datatype: double precision
Default: For single point energy calculation, 1.0e-6. Tight convergence for gradient calculation, 1.0e-8.
thresh_overlap
Description: Overlap cutoff threshold for internally contracted basis.
Datatype: Double precision
Default: 1.0e-9
frozen
Description: Freeze core orbitals.
Datatype: bool
Default: true
ncore
Description: Number of frozen core orbitals.
Datatype: int
Default: If
frozen
is true, subvalence orbitals are frozen. If false, zero.nfrozenvirt
Description: Number of frozen virtual orbitals.
Datatype: int
Default: 0
block_diag_fock
Description: Using a block-diagonal zeroth-order Hamiltonian
Datatype: bool
Default: false.
maxiter
Description: Maximum number of iterations in CASPT2 calculations.
Datatype: int
Default: 50
maxtile
Description: Maximum number of orbitals in a single data tile used in CASPT2.
Datatype: int
Default: 10
davidson_subspace
Description: Number of vectors retained in the limited-memory Davidson algorithm.
Datatype: int
Default: 10
Recommendation: Reduce if an insufficient amount of memory is available (do not reduce to a value lower than 3).
Example¶
Sample input¶
{ "bagel" : [
{
"title" : "molecule",
"basis" : "svp",
"df_basis" : "svp-jkfit",
"angstrom" : true,
"geometry" : [
{ "atom" : "O", "xyz" : [ 0.000, 0.000, 1.210 ]},
{ "atom" : "O", "xyz" : [ 0.000, 0.000, 0.000 ]}
]
},
{
"title" : "hf",
"charge" : "+2"
},
{
"title" : "dhf",
"charge" : "+2"
},
{
"title" : "zcasscf",
"algorithm" : "second",
"charge" : "0",
"state" : [0, 0, 1],
"thresh" : 1.0e-7,
"nclosed" : 7,
"nact" : 2
},
{
"title" : "relsmith",
"method" : "caspt2",
"sssr" : "false",
"ncore" : 2,
"ms" : "true",
"xms" : "true",
"shift" : "0.0"
}
]}
from which one obtains:
* Zeroth order energy : state 0 -0.4311850266
* Zeroth order energy : state 1 -0.4310720127
* Zeroth order energy : state 2 -0.4310720127
---- iteration ----
0 -0.40810539 0.00207948 1.70
1 -0.40848834 0.00016074 1.74
2 -0.40849019 0.00000849 1.71
3 -0.40849020 0.00000034 1.70
0 -0.40811484 0.00207947 1.71
1 -0.40849779 0.00016074 1.68
2 -0.40849965 0.00000849 1.69
3 -0.40849965 0.00000034 1.75
0 -0.40811484 0.00207947 1.73
1 -0.40849779 0.00016074 1.69
2 -0.40849965 0.00000849 1.69
3 -0.40849965 0.00000034 1.71
-------------------
* RelCASPT2 energy : state 0 -149.9873960122
* RelCASPT2 energy : state 1 -149.9873936904
* RelCASPT2 energy : state 2 -149.9873936904
* MS-RelCASPT2 Heff
(-149.9873960122,-0.0000000000)(0.0000000000,0.0000000000)(0.0000000000,-0.0000000000)
(0.0000000000,-0.0000000000)(-149.9873936904,-0.0000000000)(0.0000000000,0.0000000000)
(0.0000000000,0.0000000000)(0.0000000000,-0.0000000000)(-149.9873936904,-0.0000000000)
* MS-RelCASPT2 rotation matrix
(1.0000000000,0.0000000000)(0.0000000000,0.0000000000)(0.0000000000,0.0000000000)
(0.0000000000,0.0000000000)(-0.7112091498,0.4043385965)(0.0936202837,-0.5673861886)
(0.0000000000,0.0000000000)(-0.4948015439,-0.2930243620)(-0.7669166768,0.2848630658)
* MS-RelCASPT2 energy : state 0 -149.9873960122
* MS-RelCASPT2 energy : state 1 -149.9873936904
* MS-RelCASPT2 energy : state 2 -149.9873936904
References¶
BAGEL References¶
Description of Reference | Reference |
---|---|
SMITH3 | M. K. MacLeod and T. Shiozaki, J. Chem. Phys. 142, 010507 (2015). |
Relativistic CASPT2 | T. Shiozaki and W. Mizukami, J. Chem. Theory Comput. 11, 4733 (2015). |
General References¶
Description of Reference | Reference |
---|---|
CASPT2 | K. Andersson, P.-Å. Malmqvist, and B. O. Roos, J. Chem. Phys. 96, 1218 (1992). |
MS-CASPT2 | J. Finley, P.-Å. Malmqvist, B. O. Roos, and L. Serrano-Andres, Chem. Phys. Lett. 288, 299 (1998). |
XMCQDPT2 | A. A. Granovsky, J. Chem. Phys. 134, 214113 (2011). |
XMS-CASPT2 | T. Shiozaki, W. Győrffy, P. Celani, and H.-J. Werner, J. Chem. Phys. 135, 081106 (2011). |