Input

The ascii input files for DIRAC, as available in the database directory $ADFHOME/atomicdata/Dirac, have a structure as described below. With this information you should be able to construct alternative input files, with other frozen cores for instance.

1 Title (60 characters at most). Plays no role

2 Ngrid, Nshell, rmin, rmax, Z, Xion, Anuc
Ngrid=number of radial grid points, in which the core potentials are computed.
Nshell=number of atomic orbital shells
rmin, rmax=minimum and maximum radial grid values
Z=nuclear charge
Xion=net charge of the 'atom'
Anuc=atomic weight

3 Pinit, Pfinal, eps, del, delrv
Pinit, Pfinal= initial and final density iteration averaging factors. Each iteration cycle changes the actual averaging factor by taking the average of the previous and the final one, starting with the 'initial' one.
eps=Exp(-sqrt(eps)) is set to zero, so eps determines the exponential underflow control.
del=absolute convergence criterion for orbital eigenenergies.
delrv=convergence criterion on the potential (multiplied by the radial distance r).

4 Idirc, Nmax, Ndebu, Nprin, Ipun, Ircor, Iwcor
Idirc=zero for non-relativistic, otherwise one.
Nmax=maximum number of iterations allowed to reach convergence.
Ndebu=non-zero for additional output (for debugging purposes mainly)
Nprin=print parameter. Use 2 or larger to get the orbitals printed.
Ipun=punched output is produced if Ipun is non-zero. (out-of-date)
Ircor=number of core orbitals from the fully relativistic run, to be kept frozen in the subsequent (if any) first-order perturbation calculation.
Iwcor=number of core orbitals used to construct the core density and core potential, that are output on TAPE12. So, here you specify the relativistic core.

5 Xalph, Xlatt, Rnuc
Xalph= Exchange parameter in the Xalpha formalism.
Xlatt=Coulomb tail parameter
Rnuc=size of nuclear radius, in bohr. If set to 1.0 or larger, it is recomputed as 0.0000208*Anuc**(1/3)

6 For each orbital shell:
N, L, J, E, Z, D
N, L, J = The usual orbital quantum numbers. J is used only for relativistic runs.
E = Initial estimate of orbital energy, in atomic units.
Z = Number of electrons on the shell
D = Initial estimate of the error in the orbital energy

7 Icorp, Npcl, Demp, Peps
Icorp = If 1 (one): Do a first order perturbation calculation after the fully relativistic run. This option plays no role in the current application for ADF.
Npcl = Maximum number of cycles in the perturbation calculation.
Demp = Damping factor in the perturbation iterations
Peps = Convergence criterion in the perturbation iterations.