optking(1)																optking(1)

       cceom - equation of motion coupled cluster energy program

       DESCRIPTION

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

       COMMAND LINE ARGUMENTS

       After internal coordinates are detected or generated, optking will enter a run-time mode dependent on command line arguments.

       --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

       REFERENCES

       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).

       EOM_REFERENCE = integer
	      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.

       STATES_PER_IRREP = array of integers
	      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.

       PROP_SYM = integer
	      specifies the symmetry of the state that should be used to compute properties.  defaults to the last  irrep  for	which  states  are
	      requested.

       PROP_ROOT = integer
	      specifies  the  number  of  the  root  (within  its  irrep) that should be used to compute properties.  defaults to the highest root
	      requested.

       EXCITATION_RANGE = excitation_range
	      used to generate initial guesses.  the larger the value, the more initial guesses are made in the Davidson algorithm.

       RESIDUAL_TOL = integer
	      Davidson algorithm will converge until the norm of the residual vector is less than 10^(-integer).  default if 4.

       EVAL_TOL = integer
	      Davidson algorithm will converge until the change in the excitation energy is less than 10^(-integer).  default if 6.

								     Sept 2002								optking(1)