NAME¶
mp2 - Moller-Plesset Perburbation Theory
DESCRIPTION¶
The module determines the second-order Moller-Plesset energy and one-particle
density matrix (OPDM) for RHF, UHF, and ROHF (using semicanonical orbitals)
references. Frozen orbitals can be used when computing the energy but not the
OPDM.
REFERENCES¶
Original Moller-Plesset paper:
- 1.
- C. Moller and M. S. Plesset, "Note on an Approximation
Treatment for Many-Electron Systems," Phys. Rev. 46, 618 (1934).
Open-Shell Perturbation Theory
- 1.
- T. D. Crawford, H. F. Schaefer, and T. J. Lee, "On the
energy invariance of open-shell perturbation theory with respect to
unitary transformations of molecular orbitals," J. Chem. Phys. 105,
1060 (1996).
MP(2) Gradient Theory:
- 1.
- M. Frisch, M. Head-Gordon, and J. Pople, "A Direct MP2
Gradient Method," Chem. Phys. Lett. 166, 275 (1990).
- 2.
- I. Nielsen, "A new direct MP2 gradient algorithm with
implementation on a massively parallel computer," Chem. Phys. Lett.
255, 210 (1996).
Input for this program is read from the file input.dat. The following keywords
are valid:
- WFN = string
- Specifies the type of wave function desired. The only valid
entry at the present is MP2. There is no default.
- REFERENCE = string
- Specifies the type of orbitals used for the
single-determinant reference function. Valid entries include RHF, UHF, and
ROHF. There is no default.
- PRINT = integer
- Determines the verbosity of the output. A value of 0 (the
default) specifies minimal printing.
- CACHETYPE= string
- Selects the priority type for maintaining the automatic
memory cache used by the DPD codes. (See libdpd.html for further details.)
A value of LOW (the default) selects a "low priority"
scheme in which the deletion of items from the cache is based on
pre-programmed priorities. A value of LRU selects a "least
recently used" scheme in which the oldest item in the cache will be
the first one deleted.
- CACHELEV= integer
- Selects the level of automatic cacheing desired in the
storage of various amplitudes, integrals, and intermediates in the coupled
cluster procedure. A value of 0 retains no quantities in cache, while a
level of 6 attempts to store all quantities in cache. For particularly
large calculations, a value of 0 may help with certain types of memory
problems. The default is 2, which means that all four-index quantites with
up to two virtual-orbital indices (e.g., <ij|ab> integrals) may be
held in the cache.
- OPDM = boolean
- If TRUE calculate the one-particle density matrix
and make OPDM_WRITE default to TRUE. The default value of
OPDM is FALSE.
- OPDM_WRITE = boolean
- Flag for whether or not to write the one-particle density
matrix to disk.
- OPDM_PRINT = boolean
- Flag for whether or not to print the one-particle density
matrix.