MOLPRO

25 EXCITED STATES WITH EQUATION-OF-MOTION CCSD (EOM-CCSD) 189
saved in DMX, its pure electron part in DMXE, transition moment – in TRDMX (left and right transition
moments are stored separately). If TRANS=2, transition moments among excited states
are also calculated. If DENSAVE=record.ifil is specified, excited-state densities (and transition
densities, if TRANS=2) are saved to record.ifil, otherwise they are saved to the record given in
DM card.
When properties are needed, the left EOM-CCSD wave functions are calculated first. It is possible
to use them as starting guesses for the right EOM-CCSD wave functions. This option
is controlled by STARTLE (default 0). If STARTLE=1, left vectors are just used as a start
for right vectors; if STARTLE=2, starting vectors, obtained from the left vectors are additionally
biorthogonalized to the left vectors; finally, if STARTLE=3, also the final right vectors are
biorthogonalized to the left vectors. The last possibility is of particular importance for degenerate
states.
It is possible to make the program to converge to a vector, which resembles a specified singles
vector. This option is switched on by FOLLOW=n card (usually n=2 should be set). FOLLOW
card should be always accompanied with EXFILE=record.ifil card, where record.ifil contains
singles vectors from a previous calculation, see section 25.4.3.
25.2 Options for EOMPAR card
Normally, no further input is needed. However, some defaults can be changed using the EOMPAR
directive:
EOMPAR, key1=value1, key2=value2,. . .
where the following keywords key are possible:
MAXDAV=nv
INISINGL=ns
INIDOUBL=nd
INIMAX=nmax
Maximum value of expansion vectors per state in Davidson procedure
(default 20).
Number of singly excited configurations to be included in initial Hamiltonian
(default 20; the configurations are ordered according to their
energy). Sometimes INISINGL should be put to zero in order to
catch states dominated by double excitations.
Number of doubly excited configurations to be included in initial
Hamiltonian (default 10).
Maximum number of excited configurations to be included in initial
Hamiltonian. By default, nmax = ns + nd.
MAXITER=itmax Maximum number of iterations in EOM-CCSD (default 50).
MAXEXTRA=maxex
EOMLOCAL=eoml
INIMAX=ini
Maximum number of extra configurations allowed to be included in
initial Hamiltonian (default 0). In the case of near degeneracy it is
better to include a few extra configurations to avoid a slow convergence.
If set to 0, non-local calculation (default). EOMLOCAL=1 switchs on
the local module (experimental!).
Number of CSFs included in initial Hamiltonian, used only if INISINGL
and INIDOUBL are both zero.
All keywords can be abbreviated by at least four characters.