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.
Original Moller-Plesset paper:
- C. Moller and M. S. Plesset, "Note on an Approximation Treatment for Many-Electron Systems," Phys. Rev. 46, 618 (1934).
Open-Shell Perturbation Theory
- 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:
- M. Frisch, M. Head-Gordon, and J. Pople, "A Direct MP2 Gradient Method," Chem. Phys. Lett. 166, 275 (1990).
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
- OPDM_PRINT = boolean
Flag for whether or not to print the one-particle density matrix.