The Molpro Interface
Introduction
This interface supports energy and gradient evaluations with the Molpro program package.
The choice of hamiltonian includes
DFT (e.g., svwn, pbe, pw91, b3lyp, ...), Hartree-Fock, Møller-Plesset Perturbation Theory
as well as Coupled Cluster methods. Of greater interest is the use of local
approximations (see local argument) which allows for correlated calculations on systems sizes
of up to 50 atoms with large basis sets. Density fitting approximations can also be used
with Dunning basis sets (cc-pVXZ or aug-cc-pVXZ) for great computer savings.
Command Line Arguments
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| basis= |
keyword |
no |
vdz |
required basis set (Molpro internal library) |
| harmonic= |
Boolean
|
no |
yes |
Use spherical harmonic basis functions (vs. cartesians) |
| hamiltonian= |
keyword |
no |
hfscf |
choice of QM Hamiltonian: hf, mp2, mp3, mp4, ccsd, ccsd(t) and all
DFT functionals available in the MOLPRO program package. mcscf (or synonyms casscf and multi) selects an MCSCF wavefunction. rs2 performs MCSCF followed by PT2. See note 1.
|
| basisfile= |
keyword |
no |
undefined |
Basis set file |
| direct= |
Boolean
|
no |
no |
Use integral-direct calculations. See note 2. |
| local= |
Boolean
|
no |
no |
use of local approximations. Available for hamiltonian=mp2, mp3, mp4, ccsd, or ccsd(t). See note 2. |
| multipole= |
Boolean
|
no |
no |
use of multipole approximations on local methods (only for energy runs). |
| densityfit= |
Boolean
|
no |
no |
use of density fitting approximations. Available for all choices of hamiltonian. |
| verbose= |
Boolean
|
no |
yes |
Output |
| debug= |
Boolean
|
no |
no |
Output |
| read_control= |
Boolean
|
no |
no |
If set to yes, the molpro input file (generally
molpro.com) is not overwritten by ChemShell and can be changed by the user. |
| charge= |
integer |
no |
0 |
total charge |
| mult= |
integer |
no |
1 |
total spin multiplicity |
| symmetry= |
Boolean
|
no |
yes |
enable/disable symmetry. See note 2. |
| accuracy= |
keyword |
no |
medium |
Accuracy: low, medium, high,
veryhigh. See note 3 |
| basisspec= |
Tcl List
|
no |
undefined |
required basis set (ChemShell library) |
| ecpspec= |
Tcl List
|
no |
undefined |
definition of ECP (Effective Core Potentials) for heavy atoms |
| jobname= |
string |
no |
molpro |
name to use as root for file names |
| executable= |
string |
no |
molpro |
path and/or command to execute Molpro |
| memory= |
integer |
no |
64 |
allocatable memory (in Megawords) |
| restart= |
Boolean
|
no |
no |
Restart Molpro calculation (from a .wfu wavefunction file). See note 4. |
| wfu_file= |
string |
no |
[jobname][pid].wfu |
Filename for loading/saving the Molpro restart file. See note 5. |
| write_molden= |
string |
no |
undefined |
Filename for Molpro to write a MOLDEN-readable file for visualisation of geometries/molecular orbitals. |
Arguments controlling MCSCF/RS2 calculations
| Argument |
Argument type |
Mandatory |
Default |
To specify |
| mcscf_occ= |
Tcl List
|
no |
{ } |
Defines occupied orbitals. The list should be of the form {n1 n2 ...}, where n(i) specifies the number of occupied orbitals (frozen + closed + active) in irreducible representation number i. |
| mcscf_closed= |
Tcl List
|
no |
{ } |
Defines closed-shell orbitals. The list should be of the form {n1 n2 ...}, where n(i) is the number of closed-shell orbitals in irrep number i. |
| mcscf_exchange_mos= |
Tcl List
|
no |
{ } |
Alters the order of MOs in the initial MCSCF guess (useful when defining the active space). Equivalent to Molpro's rotate command with angle=0. The list should be of the form { {mo1.sym1 mo2.sym1} {mo3.sym2 mo4.sym2} {...} }, where mo1 will be swapped with mo2, mo3 with mo4, etc. |
| mcscf_wf= |
Tcl List
|
yes |
{ } |
Defines the number of electrons and wavefunction symmetry. The list should be of the form {elec sym spin}, where elec is the number of electrons, sym is the number of the irrep, and spin is the spin symmetry (0 = singlet, 1 = doublet, etc.). |
| mcscf_nroot= |
integer |
no |
1 |
MCSCF state of interest for single-state calculations (ignored for multiple state calculations). Molpro's state and weight keywords are set appropriately based on this value. |
| mcscf_gradient_accuracy= |
keyword |
no |
medium |
Convergence threshold for orbital gradient in MCSCF (medium: 1.d-2). Keywords low, medium, high, veryhigh vary by factors of 10. |
| mcscf_cp_accuracy= |
keyword |
no |
medium |
Convergence threshold for CPMCSCF gradients (multiple state gradients) in MCSCF (medium: 1.d-7). Keywords low, medium, high, veryhigh vary by factors of 100. |
| mcscf_step_accuracy= |
keyword |
no |
medium |
Convergence threshold for step length in MCSCF orbital optimization (medium: 1.d-3). Keywords low, medium, high, veryhigh vary by factors of 10. |
| rs2_shift= |
real |
no |
undefined |
Level shift to apply in RS2 calculations. |
Examples
Single point LMP2/cc-pVDZ calculation with density fitting:
energy coords=start.c energy=e theory=molpro : { hamiltonian=mp2 basis=cc-pVDZ charge=0 mult=1 local=yes densityfit=yes }
print_matrix matrix=e
Notes
-
For MCSCF/RS2 calculations with restart=no, a preliminary Hartree-Fock calculation is carried out to generate an initial orbital guess.
-
Symmetry is automatically disabled when using local approximations. It should also be disabled by the user (symmetry=no)
in the context of QM/MM calculations. Local calculations are always integral-direct.
-
The different levels of accuracy correspond to the different energy convergence thresholds. Low: 10-4 au;
medium: 10-6 au; high: 10-8 au; veryhigh: 10-10 au.
-
If a series of calculations is carried out (e.g. during a geometry optimisation), the restart option applies only to the first point. Subsequent calculations are always restarted from the previous point.
-
The .wfu file will be loaded/saved to the directory specified by Molpro's own settings. The default can be overridden by using the -W switch when calling Molpro (e.g. by adding this option to the executable keyword).
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