.TH mp2 1 " 10 August, 2003" "" ""

.SH NAME
mp2 \- Moller-Plesset Perburbation Theory

.SH DESCRIPTION
.LP
The program
.B mp2
determines the second-order Moller-Plesset energy and one-particle
density matrix (OPDM) for closed-shell systems.  Frozen orbitals can 
be used when computing the energy but not the OPDM.

.SH REFERENCES
.LP
Original Moller-Plesset paper:
.IP "1."
C. Moller and M. S. Plesset, "Note on an Approximation Treatment for 
Many-Electron Systems," Phys. Rev. 46, 618 (1934).
.LP
MP(2) Gradient Theory:
.IP "1."
M. Frisch, M. Head-Gordon, and J. Pople, "A Direct MP2 Gradient Method,"
Chem. Phys. Lett. 166, 275 (1990).
.IP "2."
I. Nielsen, "A new direct MP2 gradient algorithm with implementation on 
a massively parallel computer," Chem. Phys. Lett. 255, 210 (1996).

.SH INPUT FORMAT
.LP
Input for this program is read from the file input.dat. The following
keywords are valid:

.IP "\fBWFN =\fP \fIstring\fP"
Specifies the type of wave function desired. The only valid entry
at the present is \fIMP2\fP. There is no default.

.IP "\fBREFERENCE =\fP \fIstring\fP"
Specifies the type of orbitals used for the single-determinant
reference function. The only valid entry at the present is \fIRHF\fP.  
There is no default.

.IP "\fBPRINT =\fP \fIinteger\fP"
Determines the verbosity of the output.  A value of 0 (the default)
specifies minimal printing.

.IP "\fBCACHETYPE=\fP \fIstring\fP"
Selects the priority type for maintaining the automatic memory cache
used by the DPD codes.  (See libdpd.html for further details.)  A
value of \fILOW\fP (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 \fILRU\fP selects a
"least recently used" scheme in which the oldest item in the cache
will be the first one deleted.

.IP "\fBCACHELEV=\fP \fIinteger\fP"
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.

.IP "\fBOPDM =\fP \fIboolean\fP"
If \fBTRUE\fP calculate the one-particle density matrix and 
make \fBOPDM_WRITE\fP default to \fBTRUE\fP.  The default value 
of \fBOPDM\fP is \fBFALSE\fP.

.IP "\fBOPDM_WRITE =\fP \fIboolean\fP"
Flag for whether or not to write the one-particle density matrix
to disk.

.IP "\fBOPDM_PRINT =\fP \fIboolean\fP"
Flag for whether or not to print the one-particle density matrix.


