.TH cceom 1 "Sept 2002" "" ""
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.  \" Notice of Document Modification
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.  \"   man page created by Rollin King, Sept 2002
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.LP NAME
cceom \- equation of motion coupled cluster energy program

.LP 
\fBDESCRIPTION\fP
.LP
The program
.B cceom
calculates EOM-CCSD energies using a Davidson algorithm to solve
for the right-hand eigenvectors of the CC Hamiltonian.

.LP
\fBCOMMAND LINE ARGUMENTS\fP
.LP
After internal coordinates are detected or generated, optking will
enter a run-time mode dependent on command line arguments. 
.LP
.nf
--dot_with_Lg    \-  check the orthogonality of the excited right-hand eigenvector with
                 \-  the ground state left eigenvector, lambda.  cclambda must be run
                 \- first for this to work
.fi

.LP
\fBREFERENCES\fP
.IP "1."
The equation of motion coupled-cluster method.  A systematic biorthogonal approach
to molecular excitation energies, transition probabilities, and excited state properties,
J. F. Stanton and R. J. Bartlett, J. Chem. Phys. 98, 7029 (1993).

.IP "\fBEOM_REFERENCE =\fP \fIinteger\fP"
specifies the algorithm used by cceom.  useful for debugging.  also
must currently be set to ROHF, if you want to get triplet excited states
from a singlet ground state.  The default is whatever "REFERENCE" is.

.IP "\fBSTATES_PER_IRREP =\fP \fIarray of integers\fP"
specifies the number of states of each irreducible representation
desired.  For example, in C2v symmetry, (0 2 0 0) specifies two excited
states of A2 symmetry to be solved, regardless of the symmetry of the
ground state.

.IP "\fBPROP_SYM =\fP \fIinteger\fP"
specifies the symmetry of the state that should be used to compute properties.
defaults to the last irrep for which states are requested.

.IP "\fBPROP_ROOT =\fP \fIinteger\fP"
specifies the number of the root (within its irrep) that should be used
to compute properties.  defaults to the highest root requested.

.IP "\fBEXCITATION_RANGE =\fP \fIexcitation_range\fP"
used to generate initial guesses.  the larger the value, the more initial
guesses are made in the Davidson algorithm.

.IP "\fBRESIDUAL_TOL =\fP \fIinteger\fP"
Davidson algorithm will converge until the norm of the residual vector is
less than 10^(-integer).  default if 4.

.IP "\fBEVAL_TOL =\fP \fIinteger\fP"
Davidson algorithm will converge until the change in the excitation energy
is less than 10^(-integer).  default if 6.